JP7198398B1 - Surface-treated inorganic particles, inorganic particle-containing composition, thermally conductive cured product, structure and laminate - Google Patents

Abstract

The present invention provides surface-treated inorganic particles capable of forming a curable composition having good handling properties and storage stability, and capable of forming a cured product having good thermal conductivity. A surface-treated inorganic particle (D) comprises thermally conductive inorganic particles (A) having an average primary particle diameter of 0.05 to 100 μm and a coating layer. The thermally conductive inorganic particles (A) are at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, boehmite, and aluminum nitride, and the coating layer contains 50% by mass of a component derived from a specific silane compound. In addition, the surface-treated inorganic particles (D) have a water content of 0.2% by mass or less and a hydrophobicity of 35% or more. The amount of the silane compound is 0.05 to 3% by mass with respect to the particles (D). [Selection figure] None

Description

The present disclosure relates to thermally conductive cured products, structures and laminates, as well as surface-treated inorganic particles used in their production and compositions containing the same.

As electronic devices and batteries installed therein become smaller, more sophisticated, and more multi-functional, the development of more and more efficient heat dissipation technology is required. Insufficient heat radiation hinders the normal operation of electronic devices, and may cause deterioration, failure, or damage.

As a heat dissipation technique, there is a method of bringing a metal plate, a heat sink, a thermally conductive sheet, or a thermally conductive cured material layer into contact with a heating element.

The thermally conductive cured material layer is obtained, for example, by applying a paste of a curable composition containing thermally conductive inorganic particles, or by injecting the curable composition between objects to be bonded and then curing the composition. . Inorganic particles such as aluminum oxide, aluminum nitride, and aluminum hydroxide are known as thermally conductive inorganic particles. These inorganic particles are often selected mainly from the viewpoint of thermal conductivity and availability of the material.

The thermally conductive cured material layer has a higher volume concentration of the thermally conductive inorganic particles, and the higher the density of the particles, the better the thermal conductivity. However, when the thermally conductive inorganic particles are blended into the paste at a high concentration, the viscosity and thixotropic properties increase, making coating or injection difficult. Moreover, even if a cured product can be obtained from such a paste, there is a problem that good thermal conductivity cannot be obtained due to poor packing properties of the thermally conductive inorganic particles and poor evacuation of air bubbles.

Patent Document 1 describes that wettability in an epoxy resin medium is improved by treating the surface of aluminum oxide with a silane coupling agent. Patent Document 2 describes that the surface of aluminum oxide is treated with a silane coupling agent to make the surface hydrophobic. Further, Patent Document 3 discloses the use of a phosphate ester-based anionic dispersant as a dispersant for dispersing alumina using a polyol compound and a polyisocyanate compound as media, and the viscosity is improved. is stated.

In Patent Document 4, a silane coupling agent is applied to each of boron nitride and alumina, which are thermally conductive inorganic particles, and a polymerizable compound (polymerizable oxiranyl compound, polymerizable amine compound) is used to bond between particles. and has excellent adhesion between metal/metal, metal/semiconductor, and metal/resin. Furthermore, in Patent Document 5, by kneading three types of alumina particles with different particle sizes into a main composition containing a polyol and a curable composition containing a polyisocyanate, thermal conductivity, insulation, viscosity It is described that a two-liquid type urethane adhesive composition having excellent thixotropic properties can be obtained.

Patent Document 6 discloses a polyurethane resin composition containing an inorganic substance, a polyisocyanate, and a mixture of two polyols having different ranges of number average molecular weight and amount. Further, Patent Document 7 discloses a polyurethane resin composition containing a hydroxyl group-containing compound, an isocyanate group-containing compound, and an inorganic filler selected from alumina, aluminum hydroxide, and the like. Furthermore, Patent Document 8 discloses a polyurethane resin composition containing a coated metal hydroxide as a flame retardant and a phosphorus-containing flame retardant, and having hydrotalcite and/or phyllosilicate as essential components.

JP 2016-104832 A JP-A-2005-306718 WO2019/190107 WO2019/139057 WO2018/212553 JP 2010-248350 A WO2015/068418 WO2013/135680

Surface-treated inorganic particles are particles having a structure in which a coating layer (surface treatment layer) is formed around an inorganic core particle. Depending on the chemical structure of the material used to form the coating layer, the polarity and reactivity varies greatly. The properties of the formed surface treatment layer have a large effect on the hygroscopicity of the particles and wettability to the medium, as well as the viscosity, dispersion stability and reactivity of the resulting slurry, so the selection of its chemical structure is important. Become.

Thermally conductive inorganic particles having various compositions, shapes, surface treatment conditions and primary particle sizes are already on the market. These inorganic particles greatly differ in formability of a surface treatment layer, chemical structure of a suitable dispersant, wettability to a medium, etc., depending on the surface composition of the particles.

In a curable composition using a polyisocyanate compound, the hydrophilicity of the surface treatment layer, the hydrophobicity balance, and the control of the reactivity of the functional groups are not sufficient. There were problems with handling and storage stability. As a result, the curability and thermal conductivity of the resulting cured product were also insufficient.

The present disclosure has been made in view of the above background, and includes surface-treated inorganic particles for a polyisocyanate-based composition that can provide an inorganic particle-containing composition that has good handling properties and good storage stability. An object of the present invention is to provide an inorganic particle-containing composition containing the above inorganic particles, and a thermally conductive cured product, a structure and a laminate obtained by curing the composition.

As a result of extensive studies, the present inventors have found that the above problems can be solved in the following aspects, and have completed the present disclosure.
[1]: Surface-treated inorganic particles (D ) and
The thermally conductive inorganic particles (A) are at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, boehmite, and aluminum nitride,
The coating layer is
General formula (1): Si(R ¹ )(R ² )(R ³ )(R ⁴ )
Having 50% by mass or more of a component derived from a silane compound represented by
However, two of R ¹ to R ⁴ in general formula (1) independently represent an alkoxy group or an aryloxy group, and the other two independently represent an unsubstituted alkyl group or a substituted and at least one selected from the group consisting of a phenyl group, or three of R ¹ to R ⁴ independently represent an alkoxy group or an aryloxy group, and one represents at least one selected from the group consisting of an unsubstituted alkyl group, an alkyl group having a substituent, and a phenyl group, the substituent being a (meth)acrylic group or an isocyanate group;
The silane compound is 0.05 to 3% by mass with respect to 100% by mass of the surface-treated inorganic particles (D),
Surface-treated inorganic particles (D) for polyisocyanate-based compositions, having a water content of 0.2% by mass or less and a degree of hydrophobicity of 35% or more.
[2]: In the general formula (1), the substituent is a (meth)acryl group, the alkoxy group has 1 to 10 carbon atoms, the aryloxy group has 6 to 10 carbon atoms, and the unsubstituted alkyl group The surface-treated inorganic particles (D) according to [1], wherein the number of carbon atoms is selected from 1 to 10, and the degree of hydrophobicity is 40 to 95%.
[3]: The surface-treated inorganic particles (D) according to [1] or [2], wherein the thermally conductive inorganic particles (A) are non-spherical particles.
[4]: Dx/Ax = 0.3 to 0.8, where Ax is the specific surface area of the thermally conductive inorganic particles (A) and Dx is the specific surface area of the surface-treated inorganic particles (D). ] to [3] The surface-treated inorganic particles (D) according to any one of the above.
[5]: Dy/Ay=0.05 to 1, where Ay is the water content of the thermally conductive inorganic particles (A) and Dy is the water content of the surface-treated inorganic particles (D). [4] The surface-treated inorganic particles (D) according to any one of them.
[6]: The surface-treated inorganic particles (D) according to any one of [1] to [5], having a powder particle size D50 of 1 to 100 μm and a bulk density of 0.3 to 2 g/cm ³ .
[7]: containing inorganic particles (E) and a reactive organic solvent (C),
The inorganic particles (E) are
The surface-treated inorganic particles (D) according to any one of [1] to [6],
Optionally surface-treated thermally conductive inorganic particles (A) that do not correspond to surface-treated inorganic particles (D), and surface-treated inorganic particles (D) and thermally conductive inorganic particles that do not correspond to (A) Any one or more of the thermally conductive fillers (F) that may be
At least including surface-treated inorganic particles (D) as inorganic particles (E),
The thermally conductive filler (F) is an inorganic filler with a thermal conductivity of 5 W/(m K) or more,
The reactive organic solvent (C) is an inorganic particle-containing composition containing a polyisocyanate compound (C1).
[8]: The inorganic particle-containing composition according to [7], further comprising a dispersant (B).
[9]: The inorganic particle-containing composition according to [7] or [8], wherein the reactive organic solvent (C) further contains a polyol compound (C2).
[10]: Contains 5 to 40 parts by mass of a reactive organic solvent (C) and 0.01 to 4 parts by mass of a dispersant (B) per 100 parts by mass of the inorganic particles (E),
The inorganic particle-containing composition according to any one of [7] to [9], wherein the dispersant (B) has a water content of 1% by mass or less.
[11]: The inorganic particle-containing composition according to any one of [7] to [10], containing 70 to 95% by mass of the inorganic particles (E).
[12]: The inorganic particle-containing composition according to [7] to [11], which contains 10 to 100% by mass of the surface-treated inorganic particles (D) in 100% by mass of the inorganic particles (E).
[13]: the amount of the surface-treated inorganic particles (D) contained in 100% by mass of the inorganic particles (E) is 10 to 100% by mass;
When the inorganic particles (E) are 100% by mass, the inorganic particles (a1) having an average primary particle diameter of 0.05 μm or more and 10 μm or less are 10 to 30% by mass, and the inorganic particles (a2) having an average primary particle diameter of more than 10 μm and 30 μm or less. 30 to 70% by mass, 15 to 40% by mass of inorganic particles (a3) having an average primary particle diameter of more than 30 μm and 100 μm or less, and the total of (a1), (a2) and (a3) is 80 to 100% by mass. ,
The reactive organic solvent (C) contains a polyisocyanate compound (C1) and a polyol compound (C2) as main components,
[7] to [12] wherein the amount of the reactive organic solvent (C) is 5 to 40 parts by mass and the amount of the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E) ] The inorganic particle-containing composition according to any one of above.
[14]: The inorganic particle-containing composition according to any one of [7] to [13], wherein the polyisocyanate compound (C1) has a viscosity of 10 to 10,000 mPa·s at 25°C.
[15]: The total surface area of the inorganic particles (a1) to (a3) is Xm ² per 100 g of the inorganic particles (E), and the general formula (1) constituting the coating layer of the surface-treated inorganic particles (D) The inorganic particle-containing composition according to [13], wherein (Y/X)×1000 is from 1.0 to 5.0, where Yg is the total amount of the silane compounds represented by.
[16]: containing a dispersant (B), wherein the dispersant (B) is
an anionic surfactant having a carboxyl group, or
The inorganic particle-containing composition according to any one of [7] to [15], comprising a polymeric dispersant having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 500 to 100,000.
[17]: containing a dispersant (B), wherein the dispersant (B) is
The inorganic material according to any one of [7] to [16], comprising a polymeric dispersant having a polyether structure or a polyester structure, having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 1,000 to 50,000. Particle-containing composition.
[18]: containing a dispersant (B), wherein the dispersant (B) is
A polymeric dispersant having a carboxyl group, an acid value of 5 to 150 mgKOH/g, an amine value of 0 to 30 mgKOH/g, and a weight average molecular weight of 1,000 to 50,000,
[7] to [17], wherein the reactive organic solvent (C) is 5 to 40 parts by mass and the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E). Any inorganic particle-containing composition.
[19]: a polymer containing a dispersant (B), wherein the dispersant (B) is a polymeric dispersant having a polyether structure or a polyester structure, and a polymer having a polyether structure or a polyester structure in its main chain; and the inorganic particle-containing composition according to any one of [7] to [18], which is at least one selected from the group consisting of a vinyl polymer having a polyether structure in a side chain.
[20]: The inorganic particle-containing composition according to any one of [7] to [19], wherein the viscosity change rate after 3 hours at 35°C is 0.8 to 3.0.
[21]: A thermally conductive cured product having a thermal conductivity of 1 to 8 W/(m·K), obtained by curing the inorganic particle-containing composition according to any one of [7] to [20].
[22]: The thermally conductive cured product according to [21], which has a film thickness of 0.01 to 10 mm.
[23]: A member (M1), a member (M2), and the thermally conductive cured product according to [21] or [22] formed between the member (M1) and the member (M2) Structure.
[24]: A laminate comprising a sheet-like substrate (S1), the thermally conductive cured product according to any one of [21] to [23], and a sheet-like substrate (S2) in this order.

According to the present disclosure, a surface-treated inorganic particle for a polyisocyanate-based composition that can obtain an inorganic particle-containing composition having good handling properties and good storage stability, an inorganic particle-containing composition containing the same, and , the excellent effect of being able to provide a thermally conductive cured product, a structure and a laminate obtained by curing the composition.

The present disclosure will be described in detail below. It goes without saying that other embodiments are also included in the scope of the present disclosure as long as they match the gist of the present disclosure. In addition, in this specification, the numerical range specified using "-" shall include the numerical values described before and after "-" as the range of lower and upper values. Moreover, in this specification, the terms "film" and "sheet" have the same meaning and are not distinguished by thickness. In addition, unless otherwise noted, the various components appearing in the present specification may be used singly or in combination of two or more. Numerical values described in this specification refer to values obtained by methods described in [Examples] below.

1. Surface-treated inorganic particles (D)
The surface-treated inorganic particles (D) according to the present disclosure are surface-treated inorganic particles (D) for polyisocyanate-based compositions, and are thermally conductive inorganic particles (A) having an average primary particle diameter of 0.05 to 100 μm. and a coating layer formed on the surface of the thermally conductive inorganic particles (A). The thermally conductive inorganic particles (A) are at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, boehmite and aluminum nitride.
The coating layer contains 50% by mass or more of a component derived from a silane compound represented by the following general formula (1).
General formula (1): Si(R ¹ )(R ² )(R ³ )(R ⁴ )
However, two of R ¹ to R ⁴ in general formula (1) independently represent an alkoxy group or an aryloxy group, and the other two independently represent an unsubstituted alkyl group or a substituted represents at least one selected from the group consisting of an alkyl group having a group and a phenyl group, or
Three of R ¹ to R ⁴ independently represent an alkoxy group or an aryloxy group, and the other one is selected from the group consisting of an unsubstituted alkyl group, an alkyl group having a substituent, and a phenyl group. and the substituent is a (meth)acrylic group or an isocyanate group.

The amount of the silane compound represented by general formula (1) is 0.05 to 3% by mass with respect to 100% by mass of the surface-treated inorganic particles (D). Moreover, the water content (water content) of the surface-treated inorganic particles (D) is 0.2% by mass or less, and the hydrophobicity of the surface-treated inorganic particles (D) is 35% or more.

The field of application of the surface-treated inorganic particles (D) for the polyisocyanate-based composition of the present disclosure is not particularly limited, but it is suitable for polyisocyanate-based compositions containing a polyisocyanate compound, particularly for thermally conductive curing It can be suitably used as a sexual composition. The surface-treated inorganic particles (D) can be used for thermally conductive sheets, thermally conductive adhesives, semiconductor sealing package applications, component-embedded substrate applications, etc., and are particularly suitable for applications that impart thermal conductivity. . The surface-treated inorganic particles (D) are usually used in compositions containing other ingredients. The inorganic particle-containing composition of the present disclosure (hereinafter sometimes referred to as "the present composition") will be described later.

According to the surface-treated inorganic particles (D) of the present disclosure, it is possible to provide surface-treated inorganic particles (D) with which an inorganic particle-containing composition having good handling properties and good storage stability can be obtained. The main reason for this is considered to be that the presence of the coating layer stabilizes the particle surfaces of the surface-treated inorganic particles (D) to impart easy dispersibility, and more effectively suppresses moisture absorption. . A composition containing inorganic particles at a high concentration has a problem of increased viscosity and thixotropy (that is, viscosity). can be suppressed. In addition, although a composition containing inorganic particles at a high concentration tends to have poor storage stability, the use of the surface-treated inorganic particles (D) having the coating layer can suppress the degradation of storage stability. Therefore, the inorganic particle-containing composition has good curability and can provide a cured product with good thermal conductivity.

1-1. Thermally conductive inorganic particles (A)
As described above, the thermally conductive inorganic particles (A) are particles having an average primary particle diameter of 0.05 to 100 μm, and are at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, boehmite and aluminum nitride. is. Thermal conductivity, dielectric constant and specific gravity can be optimized by using such thermally conductive inorganic particles (A). The preferred range of the average primary particle size is 0.05 to 50 μm, more preferably 0.1 to 30 μm, more preferably 0.5 to 30 μm, and 0.5 to 10 μm. More preferably, it is particularly preferably 1 to 10 μm. Among the thermally conductive inorganic particles (A), aluminum oxide, boehmite and aluminum hydroxide are preferred, and aluminum oxide and aluminum hydroxide are more preferred. As for the thermally conductive inorganic particles (A) having the above average primary particle size, various commercial products and synthetic products can be used alone or in combination of two or more.

The shape of the thermally conductive inorganic particles (A) is not particularly limited, but examples thereof include spherical particles, rounded spherical particles, flake-like, scale-like, filament-like and other non-spherical particles. Among these, non-spherical particles are preferred. From the viewpoint of production cost, rounded particles or crushed powder particles are more preferred, and crushed powder particles are particularly preferred.

The sphericity of the thermally conductive inorganic particles (A) is preferably 0.5 to 1.2, more preferably 0.5 to 0.95, and 0.5 to 0.85. is particularly preferred. The sphericity can be calculated from an enlarged image of a scanning electron microscope. Select an arbitrary particle from the enlarged image of the scanning electron microscope, measure the projected area (A) and perimeter (M) of the particle, and calculate the radius ( r)=M/2π, the area of a true sphere (B)=π×(M/2π) ² is calculated. The sphericity (A/B) is calculated from the areas A and B thus measured and calculated. The sphericity is measured for 20 particles, and the average value is defined as the sphericity.

Although the aspect ratio of the thermally conductive inorganic particles (A) is not particularly limited, the aspect ratio is preferably 1.05 to 20, more preferably 1.1 to 10, more preferably 1.1. ~1.5 is particularly preferred. When the aspect ratio is 20 or less, the particles are easily packed. Moreover, when it is 1.05 or more, it can be obtained industrially at low cost.

The crushed powder of the thermally conductive inorganic particles (A) can be obtained by crushing a lumpy inorganic substance using, for example, a single-screw crusher, a twin-screw crusher, a hammer crusher, a ball mill, or the like. In general, crushed powder is inexpensive, but has a large variation in shape and particle size distribution, and has a non-uniform particle surface and a large specific surface area. As a result, the slurry becomes highly viscous and has poor storage stability, making it difficult to handle. Also, in general, spherical particles are more densely packed than non-spherical particles, and good thermal conductivity can be obtained. In the surface-treated inorganic particles (D) of the present disclosure, even when non-spherical particles such as crushed powder are used as the thermally conductive inorganic particles (A), it is possible to obtain a slurry with good viscosity and handleability. and good thermal conductivity can be obtained. The reason for this is speculative, but the surface having 50% or more of the component derived from the silane compound represented by the general formula (1) on the unstable surface (high surface free energy) formed by the crushing treatment This is considered to be due to the stabilizing effect of the adsorption of the treatment agent. Further, the formation of the coating layer on the particle surface reduces the release of water of crystallization within the particle, and the treatment agent is adsorbed so as to fill the roughness of the particle surface, thereby reducing the specific surface area. , is considered to be the effect of suppressing interactions with other components.

The water content of the thermally conductive inorganic particles (A) is preferably 0.01 to 1% by mass, more preferably 0.5% by mass or less, based on 100% by mass of the thermally conductive inorganic particles (A). It is preferably 0.3% by mass or less, more preferably 0.2% by mass or less, and particularly preferably 0.1% by mass or less. By setting the water content within this range, aggregation of particles in the surface treatment step can be suppressed.

The specific surface area of the thermally conductive inorganic particles (A) is preferably 0.1 to 10 m ² /g, more preferably 0.15 to 8 m ² /g, and more preferably 0.3 to 8 m ² /g. more preferably 2 to 8 m ² /g.

Various commercially available products can be used as aluminum oxide. For example, Showa Denko AS series (rounded alumina), Sumitomo Chemical A-21, A-26, A-210, AM-21, AM-210, AM-27, AM-28B, ALM- 41-1, ALM-43, AL-M7
3A, AL-S43B, AMS-5020F, AES-23 and the like.

Various commercially available products can be used as aluminum hydroxide. For example, Sumitomo Chemical Co., Ltd. C-12, C-31, C-310, C-305, C-301N, CL-310, CL-303, C-302A, CW-350, CW-325LV, CW-308 etc.

1-2. Coating layer In the surface-treated inorganic particles (D), the coating layer formed on the surface of the thermally conductive inorganic particles (A) contains a component derived from the silane compound represented by the general formula (1), as described above. It has 50% by mass or more.

By selecting the silane compound represented by the general formula (1), it is possible to impart hydrophobicity to the surface-treated inorganic particles (D), improve the handleability and storage stability of the present composition, and heat the cured product described later. It is highly compatible with conductivity. The silane compounds can be used alone or in combination of two or more.

The component derived from the silane compound represented by the general formula (1) is preferably contained in an amount of 70% by mass or more, more preferably 90% by mass or more based on 100% by mass of the coating layer. By containing 50% by mass or more of the above component, the thermally conductive inorganic particles (A) can be imparted with an appropriate degree of hydrophobicity, and in the polyisocyanate-based composition, both slurry viscosity and storage stability can be highly compatible. . Furthermore, powder productivity can be increased.

Silane compounds represented by general formula (1) include, for example, methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltri trialkoxysilane compounds such as ethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, phenyltrimethoxysilane;
Dialkoxysilane compounds such as dimethyldimethoxysilane, dimethyldiethoxysilane, dimethoxydiphenylsilane;
3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropyltripropoxysilane, 3-(meth)acryloxypropyltributoxysilane, 3- (meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane and other alkoxysilane compounds having a (meth)acryl group;
alkoxysilane compounds having an isocyanate group such as 3-isocyanatopropyltrimethoxysilane and 3-isocyanatopropyltriethoxysilane;

In the general formula (1), the substituent is a (meth)acryl group, the alkoxy group has 1 to 10 carbon atoms, the aryloxy group has 6 to 10 carbon atoms, and the unsubstituted alkyl group has It is more preferably selected from 1 to 10. The alkoxy group preferably has 1 to 5 carbon atoms, particularly preferably 1 to 3 carbon atoms.

The unsubstituted alkyl group directly bonded to the silicon atom is preferably linear, branched, or cyclic, more preferably linear or branched, and linear. is particularly preferred. Further, the unsubstituted alkyl group preferably has 2 to 10 carbon atoms, particularly preferably 4 to 8 carbon atoms. By setting the number of carbon atoms in the unsubstituted alkyl group within the above range, it is possible to effectively impart hydrophobicity to the particles while improving dispersibility and storage stability in the reactive organic solvent (C).

The alkyl group having a substituent directly bonded to the silicon atom is preferably linear, branched, or cyclic, more preferably linear or branched, and linear. is particularly preferred. The number of carbon atoms in the substituted alkyl group is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 2 to 4.

The silane compound represented by the general formula (1) is 0.05 to 3% by mass, preferably 0.05 to 2% by mass, and more preferably 100% by mass of the surface-treated inorganic particles (D). is 0.1 to 2% by mass, more preferably 0.1 to 1.5% by mass, and particularly preferably 0.5 to 1.5% by mass. By containing 0.05 to 3% by mass, the hydrophobicity and productivity of the surface-treated inorganic particles (D) are improved, the dispersion stability when made into a slurry is achieved, and the thermal conductivity when made into a cured product Excellent characteristics can be highly compatible.

As the silane compound of general formula (1) used for forming the coating layer, alkoxysilanes having an alkyl group or a phenyl group, silane coupling agents, silicone oligomers having an alkoxysilyl group in the molecule, and the like can be used. . Among these, alkoxysilanes or silane coupling agents having an alkyl group or a phenyl group are preferred, and alkoxysilanes having an alkyl group or a phenyl group are more preferred. As the silane compound, various commercially available products and synthetic products can be used alone, or two or more of them can be used in combination.

As one embodiment of the silane compound of general formula (1), it is preferable to have an unsubstituted alkyl group bonded to a silicon atom from the viewpoint of effectively imparting hydrophobicity to particles and suppressing hygroscopicity. Moreover, as one embodiment of the silane compound of general formula (1), it is preferable to have a phenyl group bonded to a silicon atom. By using an inorganic particle-containing composition containing such surface-treated inorganic particles (D), it is possible to obtain a cured product having good thermal conductivity.
Moreover, as one embodiment of the silane compound of general formula (1), it is preferable to have an alkyl group having a (meth)acrylic group bonded to a silicon atom. By using a polyisocyanate-based curable inorganic particle-containing composition containing surface-treated inorganic particles (D) having a coating layer containing the compound, a paste having good handling properties and good storage stability can be obtained. In addition, it becomes possible to obtain a cured product having good thermal conductivity.

Other silane compounds that can be used in combination with the silane compound of general formula (1) include, for example, the following silane coupling agents. That is, at least one hydrolyzable group such as an alkoxy group or an aryloxy group is bonded to a silicon atom, and in addition, an alkyl group, an alkenyl group, an aryl group, a styryl group, or the like having a substituent is bound to at least one. As the substituent of the alkyl group, those substituted with an amino group, an alkoxy group, an epoxy group, a mercapto group, a ureido group, an acid anhydride group, an isocyanurate group, or the like can be used.

The silane coupling agent is, for example, a tetraalkoxysilane compound such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;
alkoxysilane compounds having a vinyl group such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane;
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)- 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl) Alkoxysilane compounds having an amino group such as 3-aminopropylmethyldiethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane; 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercapto Alkoxysilane compounds having a mercapto group such as propyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane;
3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, Alkoxysilane compounds having an epoxy group such as 3-glycidoxypropylmethyldiethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane;
3-chloropropyltrimethoxysilane, styryltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate , 3-trimethoxysilylpropyl succinic anhydride and the like.

Surface treatment agents other than the silane coupling agent that can be used in combination with the silane compound of general formula (1) include various coupling agents such as titanate-based coupling agents, aluminum-based coupling agents, and zirconium-based coupling agents. ring agents, phosphate-based surface treatment agents, and the like. These surface treatment agents can be used in combination with the silane compound of general formula (1) by adding them sequentially or simultaneously.

Titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl/aminoethyl) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis( dioctylpyrophosphate)oxyacetate titanate, bis(dioctylpyrophosphate)ethylene titanate, diisopropylbis(dioctylphosphate)titanate, tetraisopropylbis(dioctylphosphite)titanate, tetraoctylbis(ditridecylphosphite)titanate and the like.

Aluminum-based coupling agents include alkylacetoacetate aluminum diisopropylate, acetomethoxyaluminum diisopropylate, acetoethoxyaluminum diisopropylate, acetoethoxyaluminum diisopropylate, acetoalkoxyaluminum diisopropylate, and aluminum di-n-butoxide. monomethyl acetate, aluminum di-n-butoxide monoethyl acetate and the like.

Zirconium-based coupling agents include tetra-normal propoxy zirconium, tetra-normal butoxy zirconium, zirconium tetraacetylacetonate, zirconium tributoxy acetylacetonate, zirconium tributoxy stearate, zirconium dibutoxybis(acetylacetonate), and zirconium. Dibutoxybis(acetylacetonate), zirconium tributoxyethylacetoacetate, zirconium monobutoxyacetylacetonatebis(ethylacetoacetate) and the like can be mentioned.

1-3. Hydrophobicity, pH, Water Content, etc. The hydrophobicity of the surface-treated inorganic particles (D) is 35% or more, preferably 40% or more, more preferably 45% or more. The degree of hydrophobicity is preferably 95% or less, more preferably 90% or less, still more preferably 85% or less, and particularly preferably 60% or less. By setting the degree of hydrophobicity to 35% or more, it is possible to achieve high compatibility between the hygroscopicity of the particles, the wettability to the reactive organic solvent (C), and the storage stability of the paste.

The pH of the surface-treated inorganic particles (D) is preferably 8-10, more preferably 8-9, and particularly preferably 8.2-8.8. By forming the coating layer so as to have a pH of 8 to 10, the productivity of the surface-treated inorganic particles (D), the hygroscopicity of the particles, and the suppression of reactivity with the polyisocyanate compound (C1) are highly compatible. be able to.

The water content of the surface-treated inorganic particles (D) is 0.2% by mass or less, more preferably 0.1% by mass or less, and 0.05% by mass in 100% by mass of the surface-treated inorganic particles (D). % or less, and particularly preferably 0.03 mass % or less. By setting the water content to 0.2% by mass or less, deterioration of the polyisocyanate compound (C1) due to water in the inorganic particle-containing composition can be suppressed. A lower limit is 0 mass %.

When Ay is the water content of the thermally conductive inorganic particles (A) and Dy is the water content of the surface-treated inorganic particles (D), Dy/Ay is preferably 0.05 to 1, preferably 0.1 to 0. 0.8 is more preferred, and 0.2 to 0.5 is particularly preferred. By setting the water content ratio in the range of 0.05 to 1, the formability of the coating layer is improved, and the hygroscopicity after surface treatment can be effectively suppressed.

The content of volatile components excluding water in the surface-treated inorganic particles (D) is preferably 0.1% by mass or less, and 0.05% by mass or less, based on 100% by mass of the surface-treated inorganic particles (D). 0.03% by mass or less is particularly preferable. The content of volatile components excluding water in the surface-treated inorganic particles (D) is calculated by subtracting the water content obtained using a Karl Fischer moisture meter from the amount of weight loss measured using a thermogravimetric meter. can. The weight loss of a thermogravimetric meter (differential thermal-thermogravimetric simultaneous measurement device (Thermo plus EVO2 TG-DTA8122, manufactured by Rigaku)) was measured by heating 5 mg of a sample to 40°C at a heating rate of 10°C/min in a nitrogen atmosphere. to 140° C. and held at 140° C. for 10 minutes.

The specific surface area of the surface-treated inorganic particles (D) is preferably 0.05 to 5 m ² /g, more preferably 0.10 to 4 m ² /g, and 0.25 to 4 m ² /g. is more preferred, and 1 to 3 m ² /g is particularly preferred.

Where Ax is the specific surface area of the thermally conductive inorganic particles (A) and Dx is the specific surface area of the surface-treated inorganic particles (D), Dx/Ax is preferably 0.2 to 0.9, preferably 0.3. 0.8 is more preferable, and 0.3 to 0.5 is particularly preferable. When the relationship is from 0.2 to 0.9, the effect of suppressing the hygroscopicity of the surface-treated inorganic particles (D) and particularly improving the viscosity and storage stability when made into a slurry can be obtained. Particles with a large specific surface area are considered to have a highly active particle surface due to their non-uniform shape, but it is thought that the formation of a coating layer can reduce the non-uniform shape and activity of the particle surface. be done.

The powder particle size (powder average particle size) D50 of the surface-treated inorganic particles (D) is preferably 1 to 100 μm, more preferably 1 to 70 μm, even more preferably 1 to 30 μm. ~10 μm is particularly preferred.
The bulk density of the surface-treated inorganic particles (D) is preferably 0.3-3 g/cm ³ , more preferably 0.5-2 g/cm ³ . By setting the powder particle size D50 and the bulk density within these ranges, the powder can be easily disintegrated in the medium while improving the handleability as the powder.

2. Production of Surface-Treated Inorganic Particles (D) The surface treatment can be carried out by a known method for modifying the surface of inorganic particles. Examples thereof include a spray method using a fluid nozzle, a dry method using a stirrer with shearing force, a mixer, etc., and a wet method using an aqueous or organic solvent as a solvent. When shearing force is applied in the surface treatment step, it is desirable to adjust the treatment so as not to cause deformation and destruction of the inorganic particles.

The spray method and the dry method are described below. For the surface-treated inorganic particles (D), for example, the thermally conductive inorganic particles (A) are placed in a container, and the surface-treating agent is sprayed or dropped while stirring and mixing, stirring is continued to homogenize the particles, and then the particles are dried. It can be manufactured by After drying, if there are aggregates, they can optionally be pulverized with a ball mill or the like.

A silane compound prepared in advance as a water and/or alcohol solution can be used. The weight ratio of water in the solvent of the silane compound solution is preferably 5 to 30%, more preferably 10 to 20%. Also, the mass ratio of the silane compound in the silane compound solution is preferably 10 to 80%, more preferably 20 to 50%.

The surface-treated inorganic particles (D) are prepared, for example, by blending a solvent component such as a silane compound, water and/or alcohol, and optionally an acidic compound, a basic compound, or a hydrolysis-condensation catalyst to form a homogeneous solution or dispersion. liquid. Then, the thermally conductive inorganic particles (A) are added thereto, sufficiently stirred and mixed and/or dispersed, and then dried.

Devices used for stirring and mixing include, for example, dispersers, Henschel mixers, Loedige mixers, planetary mixers, trimixes, homogenizer mixers, kneading and mixing devices for kneaders, tumbler mixers, vibratory stirrers, attritors, roll mills, etc. is mentioned. In stirring and mixing, it is preferable to make the mixed liquid homogeneous and fluid.

Devices used for premixing include, for example, dispersers, planetary mixers, and homogenizer mixers. In premixing, it is preferable that the mixed liquid is in a homogeneous and fluid state.

The temperature during stirring and mixing is preferably 30 to 200°C, more preferably 70 to 160°C, and particularly preferably 90 to 150°C, from the viewpoint of forming a surface treatment layer and suppressing side reactions in which surface treatment agents react with each other.

The stirring and mixing time is appropriately adjusted depending on the difference in equipment and reaction scale, but is preferably 1 to 20 hours, more preferably 1 to 10 hours, and particularly preferably 1 to 5 hours.

As the solvent component, it is preferable to use water or a water-soluble organic solvent. It is more preferable to use water or alcohols having a boiling point of 40 to 200°C, and particularly preferably to use alcohols having a boiling point of 60 to 150°C.

Moreover, an acidic compound and/or a basic compound can be blended for the purpose of adjusting the pH of the atmosphere in which the surface treatment reaction is carried out. As the acidic compound, inorganic acids such as hydrochloric acid and sulfuric acid, or various organic acids can be used. As the basic compound, ammonia, amines, ammonium salt compounds, metal hydroxides, or the like can be used. Among these, it is more preferable to use ammonia or an ammonium salt compound.

As the hydrolytic condensation catalyst for the silane compound, a known catalyst can be appropriately selected and used. Examples thereof include organometallic compounds such as organotin compounds, organotitanium compounds, organozirconium compounds, and organoaluminum compounds. These may be used alone or in combination of multiple types.

Examples of the organometallic compounds include dibutyltin dilaurate, dibutyltin dioctate, dibutyltin diacetate, dioctyltin dilaurate, dioctyltin dioctate, dioctyltin diacetate, dibutyltin bisacetylacetate, dioctyltin bisacetyllaurate, tetrabutyltitanate, Tetranonyl titanate, tetrakis ethylene glycol methyl ether titanate, tetrakis ethylene glycol ethyl ether titanate, bis(acetylacetonyl) dipropyl titanate, aluminum acetylacetonate, aluminum bis(ethylacetoacetate) mono-n-butyrate, aluminum ethyl acetoacetate di-n-butyrate and aluminum tris(ethylacetoacetate). Tetrabutyl titanate, aluminum ethyl acetoacetate di-normal butyrate, aluminum bis(ethylacetoacetate) mono-normal butyrate, and hydrolysates thereof are particularly preferred from the viewpoint of reactivity and solubility.

Equipment used in the drying process includes, for example, a box dryer, a vacuum dryer, a spray dryer, and a vibrating dryer. In the drying step, it is preferable to powderize the material while sufficiently removing volatile components such as moisture and organic solvent components. When the dried material becomes a block, good powder can be obtained by putting metal balls or the like in a dryer and stirring the material, or pulverizing the material with a pulverizer or the like after drying.

The drying temperature is preferably 70 to 300.degree. C., more preferably 80 to 200.degree. C., and particularly preferably 80 to 150.degree.

The drying time is appropriately adjusted depending on the difference in equipment, reaction scale, type and ratio of solvent components, and is preferably 1 to 20 hours, more preferably 1 to 10 hours, and particularly preferably 1 to 5 hours.

3. Inorganic Particle-Containing Composition The inorganic particle-containing composition of the present disclosure (hereinafter also referred to as "the present composition") contains inorganic particles (E) and a reactive organic solvent (C). In the present composition, at least one surface-treated inorganic particle (D) is included as the inorganic particle (E). Moreover, the reactive organic solvent (C) contains a polyisocyanate compound (C1). In addition, the "composition containing inorganic particles and the reactive organic solvent (C)" may be referred to as "slurry".

The composition can be used as a curable composition. It is particularly suitable for use as a thermally conductive curable composition. A dispersant (B) may be further added to the composition. By using the dispersant (B) together with the surface-treated inorganic particles (D), it is possible to more effectively improve the handleability and improve the storage stability.

3-1. Inorganic particles (E)
In this specification, the term “inorganic particles (E)” refers to (i) surface-treated inorganic particles (D), (ii) thermally conductive inorganic particles that do not fall under the surface-treated inorganic particles (D) and may be surface-treated Particles (A), and (iii) surface-treated inorganic particles (D) and thermally conductive fillers (F) that are not applicable to thermally conductive inorganic particles (A) and may be surface-treated. . That is, the inorganic particles (E) are at least one selected from (i) to (iii) described above. The composition contains at least one surface-treated inorganic particle (D) of (i) among the inorganic particles (E). The inorganic particles (E) of the present composition can contain the particles of (ii) or/and (iii) in combination with the surface-treated inorganic particles (D) of (i).
Here, the thermally conductive filler (F) refers to an inorganic filler having a thermal conductivity of 5 W/(m·K) or more. (ii) is a thermally conductive inorganic particle (A) having a "coating layer" that does not correspond to "a coating layer having 50% by mass or more of a component derived from a silane compound represented by the general formula (1)", and a coating Thermally conductive inorganic particles (A) having no layer are included. In addition, "inorganic filler" refers to a filler composed of an inorganic material, and "filler" is solid at room temperature and atmospheric pressure. Any substance that is insoluble even when elevated to high temperatures, especially up to their softening point or their melting point. Specific examples of the thermally conductive filler (A) include metal-based fillers and carbon-based fillers. Here, the term "metal-based filler" refers to a filler containing metal, and the term "carbon-based filler" refers to a filler containing carbon.

The amount of the inorganic particles (E) is preferably 70 to 95% by mass, more preferably 80 to 95% by mass, and even more preferably 85 to 95% by mass with respect to 100% by mass of the present composition. , 88 to 94% by weight. By blending the inorganic particles (E) at a high concentration, it becomes possible to obtain a cured product having good thermal conductivity.

When the inorganic particles (E) contained in the present composition are 100% by mass, the surface-treated inorganic particles (D) are preferably 10 to 100% by mass, more preferably 15 to 100% by mass. , more preferably 20 to 80% by mass, more preferably 20 to 65% by mass, and particularly preferably 20 to 50% by mass. By blending the surface-treated inorganic particles (D) at a ratio of 10 to 100% by mass, a composition with good handleability and good storage stability can be obtained.

3-2. Dispersant (B)
The composition may contain a dispersant (B). By adding the dispersant (B), the surface-treated inorganic particles (D) can be effectively dispersed in the reactive organic solvent (C).

The amount of the dispersant (B) with respect to 100 parts by mass of the inorganic particles (E) is preferably 0.01 to 4 parts by mass, more preferably 0.01 to 2 parts by mass, and further 0.1 to 1.5 parts by mass. Preferably, 0.25 to 1.5 parts by mass is more preferable, and 0.5 to 1.25 parts by mass is particularly preferable. By blending 0.01 to 4 parts by mass of the dispersant (B), the dispersibility and storage stability of the particles in the composition are excellent, and the curability and thermal conductivity of the composition are improved. can be pulled out.

The water content of the dispersant (B) is preferably 1% by mass or less, more preferably 0.5% by mass or less, and 0.3% by mass or less in 100% by mass of the dispersant (B). It is more preferable that the amount is 0.1% by mass or less, and it is particularly preferable that the amount is 0.1% by mass or less. By controlling the amount in the range of 1% by mass or less, deterioration of the polyisocyanate compound (C1) due to moisture can be suppressed.

The content of the volatile compound having a molecular weight of 500 or less having an active hydrogen excluding water contained in the dispersant (B) is preferably 1% by mass or less in 100% by mass of the dispersant (B). It is more preferably 0.5% by mass or less, still more preferably 0.3% by mass or less, and particularly preferably 0.1% by mass or less. The dispersant (B) may contain reaction by-products accompanying its synthesis or unreacted substances as impurities. By controlling within the range, the reaction with the curable component in the present composition can be suppressed, and the storage stability and curability of the present composition can be improved.
The content of volatile compounds having a molecular weight of 500 or less and having active hydrogen excluding water can be calculated from the peak intensity area ratio when the molecular weight distribution of the dispersant (B) is measured.

The acid value of the dispersant (B) is preferably 5 to 200 mgKOH/g, more preferably 5 to 150 mgKOH/g, even more preferably 5 to 120 mgKOH/g, particularly preferably 20 to 120 mgKOH/g. Having an acid value of 5 to 200 mgKOH/g improves the dispersibility of particles, the stability of dispersion over time, and the storage stability of pastes.

When the dispersant (B) has an acidic functional group, it can be used as a neutralized salt obtained by neutralizing the acidic functional group with a base. Bases used for neutralization include, for example, ammonia, amine compounds, or metal hydroxides such as sodium hydroxide and potassium hydroxide.

The amine value of the dispersant (B) is preferably 0 to 40 mgKOH/g, more preferably 0 to 30 mgKOH/g, still more preferably 0 to 10 mgKOH/g, and particularly preferably substantially 0 mgKOH/g.

The hydroxyl value of the dispersant (B) is preferably 0 to 30 mgKOH/g, more preferably 0 to 10 mgKOH/g, particularly preferably substantially 0 mgKOH/g.

Although the type of dispersant (B) is not particularly limited, surfactants, polymeric dispersants, and the like can be mentioned. Surfactants include anionic, cationic, amphoteric or nonionic surfactants. Suitable examples of surfactants include anionic surfactants having a carboxyl group.

An anionic surfactant having a carboxyl group can be exemplified as a preferred embodiment of the dispersant (B). Further, a polymeric dispersant having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 500 to 100,000 can be exemplified. Polymer type dispersants having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 1,000 to 50,000 and having a polyether structure or a polyester structure can also be exemplified.
A preferred embodiment of the dispersant (B) is a polymeric dispersant having an acid value of 5-120 mgKOH/g and a weight average molecular weight of 1,000-10,000. Preferable examples include polymeric dispersants having an acid value of 5 to 30 mgKOH/g, an amine value of 10 to 40 mgKOH/g, and a weight average molecular weight of 1,000 to 10,000. A particularly preferred example is a polymeric dispersant having a carboxyl group, an acid value of 5 to 120 mgKOH/g, and a weight average molecular weight of 1,000 to 10,000.
As the dispersing agent (B), various commercially available products and synthetic products can be used alone, or two or more dispersing agents can be used in combination.

A suitable example of the dispersant (B) of the present composition is a polymer having a carboxyl group, an acid value of 5 to 150 mgKOH/g, an amine value of 0 to 30 mgKOH/g, and a weight average molecular weight of 1,000 to 50,000. Some embodiments include a mold dispersant. In this case, it is preferable that the reactive organic solvent (C) is 5 to 40 parts by mass and the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E).

3-2-1. Polymer Dispersant A known dispersant can be used as the polymer dispersant. (Meth)acrylic polymers, polyurethane polymers, urethane acrylate polymers, polyether polymers, polyester polymers, and polymers having a polyether structure or polyester structure in the polymer main chain. Molecules can be used. A vinyl polymer having a polyether structure in the side chain is also suitable. As the dispersing agent (B), various commercially available products and synthetic products can be used alone, or two or more dispersing agents can be used in combination.

The polymeric dispersant is preferably a polymer having a polyether structure or polyester structure.
The polyether structure preferably has an alkyleneoxy unit, and the alkyleneoxy unit preferably has 2 to 5 carbon atoms, more preferably 2 to 3 carbon atoms, and particularly preferably 2 carbon atoms.
Further, the number of carbon atoms between the repeating units of the ester bond constituting the polyester structure is preferably 3 to 10, more preferably 4 to 7, with the α carbon constituting the ester bond being the first. , more preferably 5 to 6, and particularly preferably 6.
By using these polymers having a polyether structure or a polyester structure, it becomes possible to obtain an inorganic particle-containing composition with low viscosity and good dispersion stability over time.

The polymeric dispersant is at least one selected from the group consisting of a polymer having a polyether structure or polyester structure in its main chain, a urethane acrylate polymer, and a vinyl polymer having a polyether structure in its side chain. Preferably. Among these, polymers having a polyether structure or polyester structure in the main chain, or urethane acrylate polymers are more preferred, and polymers having a polyether structure or polyester structure in the main chain are particularly preferred. . These polymers can be synthesized by various known methods.

A polymer having a polyester structure in its main chain can be obtained, for example, by dehydration condensation of a polycarboxylic acid compound and a polyalcohol, by self-condensation of a compound having a carboxyl group and a hydroxyl group, or by ring-opening polymerization of lactones. can be obtained by Polymers obtained by ring-opening polymerization of lactones are particularly preferred. A polymer having a polyester structure can also be reacted with a dibasic acid or an acid anhydride.

A polymer having a polyether structure in its main chain is obtained, for example, by reacting a polymer having a polyalkyleneoxy chain having a reactive functional group such as a hydroxyl group at the molecular end with a dibasic acid or an acid anhydride. be able to.

As one embodiment of the dispersant (B), a polymeric dispersant having a polyether structure or polyester structure in the main chain and having a carboxyl group derived from a dibasic acid or an acid anhydride is preferred. Also, the number of carbon atoms in the alkyleneoxy unit constituting the polyether structure is preferably 2 to 5. Further, the dispersant (B) having 3 to 10 carbon atoms between the ester bonds constituting the polyester structure is preferred.

The urethane acrylate polymer is not particularly limited as long as it has a urethane bond and a (meth)acrylate structure. For example, it can be obtained by reacting a (meth)acrylic polymer having a hydroxyl group with an isocyanate compound. can.

A vinyl polymer having a polyether structure in a side chain, for example, a monomer having an ethylenically unsaturated group and a (poly)alkyleneoxy chain and a monomer having an ethylenically unsaturated group are copolymerized. can be obtained by As the monomer having an ethylenically unsaturated group, various vinyl-based monomers, (meth)acrylic-based monomers, maleic anhydride, maleimide, and the like can be used.

The polymeric dispersant preferably has a phosphate group or a carboxyl group as a functional group having an acid value, and more preferably has a carboxyl group. A suitable example of the polymeric dispersant is a polymeric dispersant having an acid value.

The weight average molecular weight of the polymeric dispersant is preferably 500 to 100,000, more preferably 1,000 to 50,000, even more preferably 1,000 to 20,000, and further preferably 1,000 to 10,000. Preferably, 1,000 to 5,000 is particularly preferred. By having a weight average molecular weight in the range of 500 to 100,000, it becomes possible to incorporate inorganic particles at a high concentration while further improving dispersion stability.

3-3. Reactive organic solvent (C)
The reactive organic solvent (C) is a medium capable of curing reaction and contains the polyisocyanate compound (C1). The reactive organic solvent (C) may further contain a polyol compound (C2). In this specification, the main component of the reactive organic solvent (C) refers to a component contained in an amount of 80 to 100% by mass with respect to 100% by mass of the reactive organic solvent (C). More preferably 95 to 100%, more preferably substantially 100%. When the polyisocyanate compound (C1) and the polyol compound (C2) are the main components of the reactive organic solvent (C), the total amount of these may be 80 to 100% by mass.

3-3-1. Polyisocyanate compound (C1)
The polyisocyanate compound (C1) is a polyisocyanate compound having an average number of isocyanate functional groups of 2 or more. The polyisocyanate compound (C1) preferably has a number average molecular weight of 100 to 10,000 and a viscosity at 25° C. of 10 to 10,000 mPa·s.

The type of polyisocyanate compound (C1) is not particularly limited, but aliphatic isocyanates, alicyclic isocyanates, and aromatic isocyanates can be used, and aliphatic isocyanates or alicyclic isocyanates are more preferably used. . Good pot life, flexibility and weather resistance can be obtained by using an aliphatic isocyanate or an alicyclic isocyanate.

Polyisocyanate compounds having two isocyanate groups in one molecule include, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2, aromatic diisocyanates such as 4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-toluidine diisocyanate, dianisidine diisocyanate, 4,4′-diphenyl ether diisocyanate;
ethylene diisocyanate, trimethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2 , 4,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates;
ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate , 1,3-tetramethylxylylene diisocyanate and other aromatic diisocyanates;
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate [alias: isophorone diisocyanate], 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, 4,4′-methylenebis(cyclohexylisocyanate), 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, alicyclic diisocyanates such as norbornane diisocyanatomethyl and dicyclohexylmethane diisocyanate; Modified products of these compounds can also be used. As these compounds, various commercial products and synthetic products can be used alone or in combination of two or more.

Further, polyisocyanate compounds having three isocyanate groups in one molecule include, for example, aromatic polyisocyanates such as 2,4,6-triisocyanatotoluene and 1,3,5-triisocyanatobenzene, lysine triisocyanate, and the like. aliphatic polyisocyanates, araliphatic polyisocyanates such as 4,4′,4″-triphenylmethane triisocyanate, and alicyclic polyisocyanates, and the trimethylolpropane adduct of the diisocyanate described above, water and a trimer having an isocyanurate ring.

A blocked isocyanate in which at least part of the isocyanate groups of the polyisocyanate compound (C1) are blocked with a blocking agent may be used. Specific examples include those obtained by blocking the isocyanate group of the polyisocyanate compound (C1) with ε-caprolactam, MEK (methyl ethyl ketone) oxime, cyclohexanone oxime, pyrazole, phenol and the like.

The number average molecular weight of the polyisocyanate compound (C1) is preferably from 100 to 10,000, more preferably from 200 to 5,000, and particularly preferably from 200 to 2,000. The number average molecular weight can be obtained by measuring in the same manner as for the dispersant (B).

The average functional number of isocyanate groups in the polyisocyanate compound (C1) is 2 or more, more preferably 2 to 4, more preferably 2 to 3, and particularly preferably 2. .

The viscosity of the polyisocyanate compound (C1) is preferably 10 to 10000 mPa s, preferably 10 to 2000 mPa s, more preferably 100 to 1000 mPa s, particularly 100 to 500 mPa s. preferable.
The viscosity of the polyisocyanate compound (C1) is measured at 25° C. using a Brookfield viscometer (“HB” manufactured by Eiko Seiki Co., Ltd., spindle SC4-14) at a spindle rotation speed of 50 rpm and a measurement time of 1 minute. This is the value obtained by
By using the polyisocyanate compound (C1) having the above molecular weight, average functional group number of isocyanate groups, and viscosity, an inorganic particle-containing composition that can obtain good adhesive strength while blending inorganic particles at a high concentration is obtained. will be obtained.

3-3-2. Polyol compound (C2)
The polyol compound (C2) is preferably a polyol compound having an average hydroxyl functional group number of 2 or more, and having a number average molecular weight of 100 to 10,000 and a viscosity of 10 to 10,000 mPa·s.

The type of polyol compound (C2) is not particularly limited, but examples include polyester polyols, polyether polyols, polyacrylic polyols, polycarbonate polyols, and castor oil-based polyols. Among these, polyester polyols and polyacrylic polyols are preferred, and polyester polyols are particularly preferred.

Various known polyester polyols can be used. Examples of polyester polyols include compounds (esterification products) obtained by an esterification reaction of one or more polyol components and one or more acid components; polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone ) and polyester polyols obtained by ring-opening polymerization of lactones;

Raw material polyol components include ethylene glycol (EG), propylene glycol (PG), diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 2-ethyl-1,3- hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, and the like. be done.
Acid components of raw materials include succinic acid, methylsuccinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1, 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, and acid anhydrides thereof etc.

The polyester polyol may be polyester urethane polyol reacted with diisocyanate, or may be reacted with acid anhydride to introduce carboxyl groups.
Diisocyanates include, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. be done.
Examples of acid anhydrides include pyromellitic anhydride, mellitic anhydride, trimellitic anhydride, and trimellitic ester anhydride.
Examples of trimellitic ester anhydrides include ester compounds obtained by subjecting an alkylene glycol or alkanetriol having 2 to 30 carbon atoms to an esterification reaction with trimellitic anhydride. Examples include trimellitate, propylene glycol bisanhydro trimellitate, and the like.

A known polyether polyol can be used. Examples of the polyether polyol include a compound (addition polymer) obtained by addition polymerization of one or more oxirane compounds using an active hydrogen group-containing compound having a plurality of active hydrogen groups in one molecule as an initiator. mentioned.

Examples of the initiator include hydroxyl group-containing compounds and amines. Specifically, two compounds such as ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, neopentyl glycol, butylethylpentanediol, N-aminoethylethanolamine, isophoronediamine, and xylylenediamine. functional initiators; trifunctional initiators such as glycerin, trimethylolpropane, and triethanolamine; and tetrafunctional initiators such as pentaerythritol, ethylenediamine, and aromatic diamines. Oxirane compounds include alkylene oxides (AO) such as ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO); tetrahydrofuran (THF), and the like.

As the polyether polyol, an alkylene oxide adduct of an active hydrogen-containing compound (also referred to as polyoxyalkylene polyol) is preferred. Among them, polyethylene glycol (PEG), polypropylene glycol (PPG), PPG with ethylene oxide (EO) added to the end (PPG-EO), and bifunctional polyether polyols such as polyalkylene glycols such as polytetramethylene glycol; glycerin Trifunctional polyether polyols such as alkylene oxide adducts of are preferred.

The number average molecular weight of the polyol compound (C2) is preferably from 100 to 10,000, more preferably from 200 to 5,000, and particularly preferably from 200 to 2,000. The number average molecular weight can be obtained by measuring in the same manner as for the dispersant (B).

The average functional number of hydroxyl groups in the polyol compound (C2) is 2 or more, more preferably 2 to 4, particularly preferably 2 to 3.

The viscosity of the polyol compound (C2) is preferably 10 to 10,000 mPa·s, preferably 10 to 2,000 mPa·s, more preferably 100 to 1,000, and particularly preferably 100 to 500.
The viscosity of the polyol compound (C2) is measured at 25° C. using a Brookfield viscometer (“HB” manufactured by Eiko Seiki Co., Ltd., spindle SC4-14) at a spindle rotation speed of 50 rpm and a measurement time of 1 minute. is the value obtained.
By using the polyol compound (C2) having the above molecular weight, average functional group number of hydroxyl groups, and viscosity, it is possible to obtain an inorganic particle-containing composition that can obtain good adhesive strength while incorporating inorganic particles at a high concentration. become.

In the present composition, the amount of the reactive organic solvent (C) with respect to 100 parts by mass of the inorganic particles (E) is preferably 5 to 40 parts by mass, more preferably 5 to 33.3 parts by mass. It is more preferably from 1 to 25 parts by mass, and particularly preferably from 5 to 18 parts by mass.

3-4. Other Ingredients The present composition may further contain leveling agents, antifoaming agents, reaction accelerators, curing catalysts, rheology modifiers, organic solvents, coloring agents, curing components such as epoxy compounds, antioxidants, etc. It is a composition containing various additives such as stabilizers, flame retardants, plasticizers, and ion scavengers. There is no particular limitation on each of these appropriately added materials, and they can be used singly or in combination of two or more. The inorganic particle-containing composition of the present disclosure can be used particularly suitably for forming a thermally conductive cured material layer.

By using a leveling agent or an antifoaming agent, the appearance and density of the cured product can be improved. Examples of leveling agents include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, polyether ester-modified hydroxyl-containing polydimethylsiloxane, and acrylic copolymers. , methacrylic copolymers, polyether-modified polymethylalkylsiloxanes, acrylic acid alkyl ester copolymers, methacrylic acid alkyl ester copolymers, and lecithin. Antifoaming agents include, for example, silicone resins, silicone solutions, copolymers of alkyl vinyl ethers, alkyl acrylates, and alkyl methacrylates, vinyl ether polymers, and olefin polymers.

The reaction accelerator is not particularly limited, and compounds commonly used as curing agents for resins obtained by reaction of ordinary polyisocyanate compounds and polyol compounds can be used. Examples thereof include amine-based compounds, amide-based compounds, acid anhydride-based compounds, phenol-based compounds, and dibutyltin compounds.
More specifically, metal-based catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dimaleate; 1,8-diaza-bicyclo(5,4,0)undecene-7,1 tertiary amines such as ,5-diazabicyclo(4,3,0)nonene-5,6-dibutylamino-1,8-diazabicyclo(5,4,0)undecene-7; reactivity such as triethanolamine tertiary amine;

The curing catalyst contributes to promoting the reaction between the polyisocyanate compound (C1) and the polyol compound (C2). Moreover, when the polyisocyanate compound (C1) is blocked, it can be deblocked with a curing catalyst. Curing catalysts include quaternary ammonium salts and the like.

Examples of flame retardants include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic filler-based flame retardants, and organic metal salt-based flame retardants.

Plasticizers include, for example, liquid paraffin.

The rheology modifier imparts thixotropy to the inorganic particle-containing composition to suppress sedimentation of the inorganic particles. It also contributes to the coatability of the composition. As the rheology modifier, various materials sold as thickeners and rheology control agents can be used.

The organic solvent is a compound different from the reactive organic solvent (C) and preferably has a boiling point of 100° C. or less. It may optionally be included to reduce viscosity to allow uniform mixing of the inorganic particle-containing composition. From the viewpoint of VOC, it is more preferable to use a solvent-free type.

A compound having two or more epoxy groups can be added as a curable component. By blending such an epoxy compound, flexibility and heat resistance can be imparted to the cured product.

The ion scavenger can adsorb ionic impurities and maintain insulation reliability when moisture is absorbed.

The present composition may further contain various other additives within a range that does not impair the effects of the present disclosure. Examples of additives include inorganic particles not included in the inorganic particles (E), such as inorganic fillers such as mica, talc, and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors, etc.), rust inhibitors, antistatic agents, lubricants, antiblocking agents, crystal nucleating agents, moisture absorbents, and catalysts for adjusting the curing reaction.

3-5. Water Content, Viscosity, etc. The water content in the composition is preferably 0.01 to 0.5% by mass, more preferably 0.01 to 0.3% by mass, and more preferably 0.01 to 0.3% by mass. 1% by weight is particularly preferred.

The viscosity of the present composition is preferably 1 to 500 Pa s, more preferably 1 to 200 Pa s, even more preferably 1 to 100 Pa s, and 1 to 50 Pa s. is more preferable, and 1 to 30 Pa·s is particularly preferable.
The viscosity value was determined by the method described in the Examples using a Brookfield viscometer (“HB” manufactured by Eiko Seiki Co., Ltd., spindle SC4-14 when the viscosity value of the sample is 200 Pa s or less, and the viscosity value is 200 Pa・When s is exceeded, spindle SC4-25) is used, the sample temperature is 25° C., the spindle rotation speed is 50 rpm, and the measurement time is 1 minute.

The viscosity change rate of the present composition after 3 hours at 35° C. is preferably 0.7 to 5.0, more preferably 0.8 to 4.0, and 0.8 to 3.0. It is more preferably 1.0 to 2.5, particularly preferably 1.0 to 2.5.
The rate of viscosity change was determined by the method described in the Examples using a Brookfield viscometer (“HB” manufactured by Eiko Seiki Co., Ltd., spindle SC4-14 when the viscosity value of the sample is 200 Pa s or less, and the viscosity value When it exceeds 200 Pa·s, it is a value calculated using the values obtained when the spindle SC4-25) is used, the sample temperature is 25° C., the spindle rotation speed is 50 rpm, and the measurement time is 1 minute.
Further, the total surface area of the inorganic particles (E) is Xm ² per 100 g of the inorganic particles (E), and the silane compound represented by the general formula (1) constituting the coating layer of the surface-treated inorganic particles (D) (Y/X)×1000 is preferably 1.0 to 5.0, where Yg is the total amount of By blending the silane compound represented by the general formula (1) within the above numerical range with respect to the specific surface area of the inorganic particles (E), suppression of moisture absorption of the particles and thermal conductivity of the cured product are highly compatible. can.

3-6. Other Preferred Embodiments As an inorganic particle-containing composition according to another preferred embodiment, inorganic particles (E) containing at least one type of surface-treated inorganic particles (D), a dispersant (B), and a polyisocyanate compound ( Some compositions containing C1) and a reactive organic solvent (C) have the following conditions. That is, when the inorganic particles (E) are 100% by mass, the inorganic particles (a1) having an average primary particle diameter of 0.05 μm or more and 10 μm or less are 10 to 30% by mass, and the inorganic particles having an average primary particle diameter of more than 10 μm and 30 μm or less ( 30 to 70% by mass of a2) and 15 to 40% by mass of inorganic particles (a3) having an average primary particle diameter of more than 30 μm and 100 μm or less, and the total of (a1), (a2) and (a3) is 80 to 100% by mass. % can be exemplified. All of the inorganic particles (a1), inorganic particles (a2) and inorganic particles (a3) are surface-treated inorganic particles (D), or any one is surface-treated inorganic particles (D) and the rest are thermally conductive inorganic particles (A ) is preferred. Furthermore, the reactive organic solvent (C) contains the polyisocyanate compound (C1) and the polyol compound (C2) as main components. Further, the amount of the reactive organic solvent (C) is 5 to 40 parts by mass and the amount of the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E).

The inorganic particles (a1) are particles having an average primary particle diameter of 0.05 μm or more and 10 μm or less, preferably 0.1 μm or more and 10 μm or less, more preferably 0.5 μm or more and 10 μm or less, and 1 μm or more and 5 μm or less. The following are particularly preferred.

The inorganic particles (a2) are particles having an average primary particle diameter of more than 10 μm and 30 μm or less, preferably 15 μm or more and 30 μm or less, particularly preferably 20 μm or more and 30 μm or less.

The inorganic particles (a3) are particles having an average primary particle diameter of more than 30 μm and 100 μm or less, preferably more than 30 μm and 70 μm or less, more preferably more than 30 μm and 50 μm or less.

By setting the average primary particle size of each of the inorganic particles (a1) to (a3) within this range, a cured product in which the particles are densely packed can be obtained, and good thermal conductivity can be obtained. .

When the amount of the inorganic particles (E) contained in the inorganic particle-containing composition is 100 parts by mass, the total amount of the inorganic particles (a1), the inorganic particles (a2), and the inorganic particles (a3) is 80 to 100 mass parts. It is preferably 90 to 100 parts by mass, more preferably 95 to 100 parts by mass, and particularly preferably substantially 100 parts by mass.

When the amount of the inorganic particles (E) contained in the inorganic particle-containing composition is 100 parts by mass, the amount of the inorganic particles (a1) is 10 to 30 parts by mass, preferably 10 to 25 parts by mass. , more preferably 15 to 25 parts by mass, particularly preferably 15 to 20 parts by mass.
The amount of the inorganic particles (a2) is 30 to 70 parts by mass, preferably 40 to 70 parts by mass, more preferably 45 to 65 parts by mass, and particularly preferably 45 to 60 parts by mass.
Further, the amount of the inorganic particles (a3) is 15 to 40 parts by mass, preferably 15 to 35 parts by mass, more preferably 15 to 30 parts by mass, further preferably 15 to 25 parts by mass, and 15 to 20 parts by mass. Especially preferred.

By setting the ratios of the inorganic particles (a1) to (a3) within this range, it is possible to obtain an inorganic particle-containing composition with good handling properties and good curability, and to obtain a cured product with good thermal conductivity. be able to obtain

Further, the amount of the inorganic particles (E) contained in the inorganic particle-containing composition is 100 g, the total surface area of the inorganic particles (a1) to (a3) is Xm ² , and the surface-treated inorganic particles (D) are (Y/X)×1000 is preferably 1.0 to 5.0, where Yg is the total amount of the silane compound represented by the general formula (1) constituting the coating layer of 2. It is more preferably 0 to 4.0, even more preferably 2.5 to 4.0, and particularly preferably 2.5 to 3.5. By blending the silane compound represented by the general formula (1) within the above numerical range with respect to the specific surface area of the inorganic particles (E), suppression of moisture absorption of the particles and thermal conductivity of the cured product are highly compatible. can.

4. Manufacture of Inorganic Particle-Containing Composition This composition comprises, for example, a polyisocyanate compound (C1) as a reactive organic solvent (C), a dispersant (B), and, if necessary, an antifoaming agent and a stabilizer. , after preparing a homogeneous solution or dispersion, add surface-treated inorganic particles (D), optionally thermally conductive inorganic particles (A), other inorganic particles, polyol compound (C2), etc., and sufficiently stir and mix. It can be manufactured by performing a dispersion treatment after

Devices used for stirring and mixing include, for example, dispersers, planetary mixers, trimixes, homogenizer mixers, kneading mixers such as kneaders, tumbler mixers, vibratory stirrers, attritors, roll mills, and the like. In stirring and mixing, it is preferable to make the mixed liquid homogeneous and fluid.

Examples of the dispersing machine used for the dispersing treatment include bead mills, colloid mills, planetary mixers, trimixes, homogenizer mixers, kneading mixers such as kneaders, attritors, roll mills, and rotation/revolution mixers. The dispersing machine to be used can be appropriately set according to the handling property of the inorganic particle-containing composition and the degree of aggregation of the inorganic particles.

The temperature during dispersion is preferably 10 to 50° C., preferably 40° C., in terms of suppressing the dispersibility of the inorganic particles (D), the chemical reaction between the dispersant (B) and the reactive organic solvent (C), and the wear of the device. The following is more preferable, and 35° C. or less is particularly preferable.

The dispersion time is appropriately adjusted while sampling the particle size of the inorganic particles. The dispersion time varies depending on the equipment, but is preferably about 0.1 to 10 hours, more preferably 0.5 to 5 hours, and particularly preferably 1 to 5 hours.

5. Thermally Conductive Cured Product and Method for Producing Same The present composition is cured to form a thermally conductive cured product, which can adhere to objects. For example, a structure including a member (M1), a member (M2), and a thermally conductive cured material formed between the member (M1) and the member (M2) can be preferably obtained.
The structure is, for example, a step of applying an inorganic particle-containing composition to the member (M1), sandwiching the curable composition with the member (M2) and then curing and bonding, or a step of bonding the member (M1) and It can be obtained by a step of injecting an inorganic particle-containing composition into the interface between the members (M2) and curing. The shape of the cured product is not particularly limited, and may be three-dimensional or layered (sheet-like).

Moreover, the shape of the member (M1) and the member (M2) is not particularly limited, and examples thereof include a three-dimensional shape and a sheet-like base material. For example, the inorganic particle-containing composition of the present disclosure can be used as an adhesive layer constituting a laminate, and includes a sheet-like substrate (S1), a thermally conductive cured product, and a sheet-like substrate (S2). and can be suitably obtained in this order.
The laminate is obtained by coating the sheet-like substrate (S1) with the inorganic particle-containing composition of the present disclosure, curing to form a sheet-like cured product, and further laminating the sheet-like substrate (S2). Obtainable. Alternatively, the inorganic particle-containing composition of the present disclosure can be applied to the sheet-like substrate (S1) and dried to form a sheet-like cured product, which can be used as a thermally conductive adhesive sheet.

When used as a thermally conductive curable composition, a portion of an electronic device or module such as a power module or battery module where heat is desired to be dissipated, and, if necessary, a heat dissipating member such as a metal plate or a heat sink, and a thermally conductive curable composition. Good heat dissipation can be obtained by bringing the cured product layers obtained from the material into contact with each other. The form of the inorganic particle-containing composition of the present disclosure used at that time is not particularly limited, but it is preferably liquid or paste. By making it into a liquid or paste form, it can be easily applied to the adhesion surface or injected into the interface between the adherends, and then cured to form a cured product layer with good adhesion. can.
When the composition is used in a semi-cured state, it can be semi-cured in the form of a sheet, brought into contact with a member to be adhered, and further cured before use. In the case of designing a solid, a powder, chip, sheet, or the like is placed on the interface of the bonding surface, heated to melt the solid inorganic particle-containing composition, and then cured. It can function as an adhesive.

The method of applying the present composition is not particularly limited. can be done. Also, various known methods such as a gravure coater can be used.

The method of curing the present composition is not particularly limited, but includes a method of aging at room temperature or under heat. The aging period for the curing reaction is, for example, about 1 to 5 days at 40°C.

The film thickness of the cured product is preferably 0.01 to 10 mm, more preferably 0.01 to 5 mm, particularly preferably 0.1 to 5 mm. By setting the thickness of the cured product within the above range, it is possible to obtain sufficient adhesive strength while obtaining good thermal conductivity.

By forming a curable composition based on the polyisocyanate compound (C1) and the polyol compound (C2), good viscoelasticity and strength can be obtained under the operating temperature environment, particularly in the temperature range of about -35°C to about +80°C. be able to.

The thermal conductivity of the cured product is preferably 1 to 8 W/(m K), more preferably 1.5 to 6 W/(m K), and more preferably 1.8 to 6 W/(m ·K), more preferably 2 to 5 W/(m·K), and particularly preferably 2.5 to 5 W/(m·K). The thermal conductivity of the cured product can be measured by the method described in Examples.

Hereinafter, the present disclosure will be described in detail based on examples, but the present disclosure is not limited to the examples. In the present examples, parts means parts by mass and % means % by mass, unless otherwise specified. Materials used in Examples and Comparative Examples are shown below. In the tables below, thermally conductive inorganic particles (A) and the like are simply described as (A) and the like.

<Thermal conductive inorganic particles (A)>
· Aluminum oxide A (HCA-40 manufactured by SHJQ Chemical Technology Co. Ltd.): average primary particle size 40 μm, specific surface area 0.157 m ² /g, crushed powder (non-spherical particles).
· Aluminum oxide B (HCA-20 manufactured by SHJQ Chemical Technology Co. Ltd.): average primary particle diameter of 25 μm, specific surface area of 0.366 m ² /g, crushed powder (non-spherical particles).
- Aluminum oxide C (YC-2 manufactured by Suzhou Ginet New Material Technology Co. Ltd.): average primary particle diameter of 2 µm, specific surface area of 5.513 m ² /g, crushed powder (non-spherical particles).
· Aluminum hydroxide A (CW-325LV manufactured by Sumitomo Chemical Co., Ltd.): non-spherical particles.
· Aluminum hydroxide B (manufacturing example 1, pulverized product): 300 parts of isopropyl alcohol and 200 parts of aluminum hydroxide A were added to a glass bottle with a capacity of 900 mL, and 200 parts of 1.25 mm Φ zirconia beads were used as media, and the mixture was 9 in a paint shaker. The aluminum hydroxide A was pulverized by stirring and mixing for a period of time. Thereafter, the obtained dispersion was filtered, and the filtered material was thoroughly dried by heating at 120° C. to obtain aluminum hydroxide B. Ground powder (non-spherical particles).
·Aluminum hydroxide C (Production Example 2): Aluminum hydroxide C was produced in the same manner as in Production Example 1, except that the stirring and mixing treatment time of the paint shaker in Production Example 1 was changed to 6 hours. Ground powder (non-spherical particles).
· Aluminum hydroxide D (Production Example 3): Aluminum hydroxide D was produced in the same manner as in Production Example 1, except that the stirring and mixing treatment time of the paint shaker in Production Example 1 was changed to 3 hours. Ground powder (non-spherical particles).
· Aluminum hydroxide E (manufacturing example 4): 100 parts of aluminum hydroxide A was charged into a stainless steel beaker and heat-treated at 235°C for 6 hours while stirring to prepare aluminum hydroxide E. The weight reduction rate of aluminum hydroxide due to the heat treatment was 5.8%. In addition, a strong diffraction pattern derived from boehmite was confirmed at 2θ=about 14.5 degrees by powder X-ray diffraction (XRD) measurement, and the boehmite conversion rate was about 25%. It is known that when aluminum hydroxide is partially converted to boehmite by heating, the conversion occurs mainly on the surface of the particles, and it can be assumed that the surface of the particles of aluminum hydroxide E is boehmite. Non-spherical particles.
Aluminum hydroxide F (Production Example 5): Aluminum hydroxide F was produced in the same manner as in Production Example 1, except that aluminum hydroxide A in Production Example 1 was changed to aluminum hydroxide E. Ground powder (non-spherical particles).

<Evaluation of Thermally Conductive Inorganic Particles (A)>
Table 1 shows the average primary particle size, water content Ay, specific surface area Ax, D50, and hydrophobicity of aluminum hydroxides A to F.
[Average primary particle size]
The average primary particle size of the thermally conductive inorganic particles (A) was determined by measuring the length of 50 particles selected from an enlarged image of a scanning electron microscope, and calculating the average value. If the particle image is elliptical, for example, the average length of the major axis and the minor axis is used.
[Water content]
The water content of the thermally conductive inorganic particles (A) was measured using a Karl Fischer moisture meter (“CA-200” manufactured by Mitsubishi Chemical Analytech Co., Ltd., coulometric measurement). 1 to 2 g of the thermally conductive inorganic particles (A) were weighed and heated at 140° C. to measure the amount of vaporized water. When the thermally conductive inorganic particles (A) were surface-treated, the measurement was performed immediately before the surface treatment.
[Hydrophobicity]
The degree of hydrophobicity of the thermally conductive inorganic particles (A) was obtained by conducting a methanol wettability test. Specifically, 0.5 g of the thermally conductive inorganic particles (A) and 50 mL of ion-exchanged water are placed in a 500 mL container at 25 ° C., methanol is added dropwise to the stirring with a stirrer, and the thermally conductive inorganic particles are The dropping amount when the entire amount of (A) was suspended in ion-exchanged water was determined. Then, it was calculated by the following formula. Here, when the entire amount of the thermally conductive inorganic particles (A) is suspended in the ion-exchanged water, it means that there are almost no inorganic particles resuspended on the liquid surface when the stirring by the stirrer is stopped. .
Hydrophobicity (%) = methanol drop amount (mL) x 100/(methanol drop amount (mL) + ion exchange water amount (mL))
[Specific surface area]
The specific surface area of the thermally conductive inorganic particles (A) was measured using Macsorb HM model-1220 (manufactured by Mounttech) and obtained as the BET specific surface area by the nitrogen gas adsorption method.
[Powder particle size D50]
The powder particle size D50 of the thermally conductive inorganic particles (A) was measured in a dry manner using a laser diffraction particle size distribution analyzer SALD-2300 manufactured by Shimadzu Corporation. The refractive index of the thermally conductive inorganic particles (A) was the documented refractive index value of the thermally conductive inorganic particles (A). For example, for aluminum oxide, the analysis was performed with the refractive index parameter set to 1.70-0.10i. From the measurement results, the particle size (median diameter) at an integrated value of 50% was calculated from the integrated (accumulated) mass percentage, and was defined as the average particle diameter D50 of the powder.

<Surface treatment agent (silane compound, etc.)>
・dimethyldimethoxysilane ・n-propyltrimethoxysilane ・hexyltrimethoxysilane ・hexyltriethoxysilane ・octyltriethoxysilane ・decyltrimethoxysilane ・hexadecyltrimethoxysilane ・dimethoxydiphenylsilane ・3-aminopropyltrimethoxysilane ・3-trimethoxysilylpropylsuccinic anhydride/3-glycidoxypropylmethyldimethoxysilane/TC-1040 (manufactured by Matsumoto Fine Chemicals Co., Ltd., phosphate ester titanium complex)

<Preparation of surface-treated inorganic particles (D), etc.>
[Example 1 (manufacturing example p1-1)]
50 parts of isopropyl alcohol and 0.08 part of hexyltriethoxysilane were placed in a stainless steel vessel and stirred with a disper to fully dissolve them. Thereafter, 99.92 parts of aluminum oxide A was charged under disper stirring, and mixed at a temperature of 70° C. for 2 hours to prepare a slurry.
The obtained slurry was taken out, transferred to a dryer, dried at 80° C. under normal pressure for 2 hours, and then dried at 100° C. under reduced pressure for 2 hours to prepare surface-treated inorganic particles (D). The resulting surface-treated inorganic particles had a water content of 0.01%, a hydrophobization degree of 84%, a particle pH of 8.8, a powder particle size D50 of 48 μm, and a bulk density of 1.8 g/mL.

[Examples 2 to 8, 12]
Surface-treated inorganic particles (D) of Examples 2 to 8 and 12 were produced in the same manner as in Example 1, except that the materials and amounts used in Example 1 were changed as shown in Table 2A.

[Example 9]
50 parts of 3-methoxybutyl acetate and 1 part of hexyltriethoxysilane were placed in a stainless steel vessel and thoroughly dissolved by stirring with a disper. After that, 99 parts of aluminum oxide C was charged under disper stirring, and mixed at a temperature of 70° C. for 2 hours to prepare a slurry.
The resulting slurry was taken out, transferred to a dryer, and dried at 120° C. under reduced pressure for 5 hours to produce surface-treated inorganic particles (D).

[Example 10]
50 parts of isopropyl alcohol and 1 part of hexyltriethoxysilane were placed in a stainless steel vessel and stirred with a disper to fully dissolve them. After that, 99 parts of aluminum hydroxide A was charged under disper stirring, and mixed at a temperature of 70° C. for 2 hours to prepare a slurry.
The resulting slurry was taken out, transferred to a dryer, dried at 80° C. under normal pressure for 2 hours, and then dried at 100° C. under reduced pressure for 2 hours to produce surface-treated inorganic particles (D).

[Example 11]
A plastic container was charged with 10 parts of hexyltriethoxysilane, 9 parts of water, and 81 parts of isopropyl alcohol, and stirred with a disper to fully dissolve them, thereby preparing a silane solution.
Next, 99 parts of aluminum hydroxide A was charged into a planetary mixer (Hibismix 2P-03, manufactured by Primix), and 10 parts of the prepared silane solution was added dropwise over 20 minutes while stirring at 20 rpm. Stirring was continued for 2 hours. The resulting mixture was taken out, transferred to a dryer, dried at 80° C. under normal pressure for 2 hours, and then dried at 100° C. under reduced pressure for 2 hours to produce surface-treated inorganic particles (D).

[Example 13]
50 parts of isopropyl alcohol and 1.2 parts of hexyltrimethoxysilane were placed in a stainless steel vessel and stirred with a disper to fully dissolve them. Thereafter, 98.8 parts of aluminum hydroxide B was charged under disper stirring, and mixed at a temperature of 70° C. for 2 hours to prepare a slurry.
The obtained slurry was taken out, transferred to a dryer, dried at 90° C. under normal pressure for 2 hours, and then dried at 100° C. under reduced pressure for 2 hours to prepare surface-treated inorganic particles (D). The resulting surface-treated inorganic particles had a water content of 0.19%, a hydrophobicity of 69%, a particle pH of 8.6, a powder particle size D50 of 1.9 μm, and a bulk density of 0.7 g/mL.

[Examples 14 to 20]
Surface-treated inorganic particles (D) of Examples 14 to 20 were produced in the same manner as in Example 13, except that the materials and amounts used in Example 13 were changed as shown in Table 2C.

[Example 21]
Surface-treated inorganic particles (D) of Example 21 were obtained in the same manner as in Example 11, except that the materials and amounts used in Example 11 were changed as shown in Table 2C.

[Comparative Examples 1, 4 to 9]
Surface-treated inorganic particles of Comparative Examples 1 and 4 to 9 were produced in the same manner as in Example 1, except that the materials and amounts used in Example 1 were changed as shown in Tables 2A and 2C.

[Comparative Example 2]
40 parts of isopropyl alcohol and 5 parts of hexyltrimethoxysilane were placed in a stainless steel container and stirred with a disper to dissolve them sufficiently. Thereafter, 95 parts of aluminum oxide C was charged under disper stirring, and mixed at a temperature of 70° C. for 1 hour to produce a slurry. The obtained slurry was taken out, transferred to a dryer, dried by heating at 200° C. for 3 hours, and then dried at 120° C. under reduced pressure for 2 hours to prepare surface-treated inorganic particles. The obtained surface-treated inorganic particles were very hard and difficult to pulverize. It can be inferred that this is because the particles of the aluminum oxide C were firmly fixed by an excessive amount of the silane compound. In Comparative Example 3, the aluminum oxide C was used as it was without surface treatment.

<Evaluation of surface-treated inorganic particles (D), etc.>
[Water content]
The water content of the surface-treated inorganic particles (D) was measured using a Karl Fischer moisture meter (“CA-200” manufactured by Mitsubishi Chemical Analytech Co., Ltd., coulometric measurement). A sample of 3 to 4 g was heated at 140° C. and the amount of vaporized water was measured.
[Hydrophobicity]
The hydrophobicity of the surface-treated inorganic particles (D) was determined in the same manner as for the thermally conductive inorganic particles (A). [pH]
The pH of the surface-treated inorganic particles (D) was determined by adding the surface-treated inorganic particles (D) to a mixed solution of IPA:water = 1:1 so that the surface-treated inorganic particles (D) became 1% by mass, and then using an ultrasonic disperser (transmission frequency: 40 kHz). , output 130 W) for 10 minutes, and the pH was determined at a temperature of 25°C.
[Specific surface area]
The specific surface area of the surface-treated inorganic particles (D) was determined by the same method as for the thermally conductive inorganic particles (A).
[Powder particle size D50]
The powder particle size D50 of the surface-treated inorganic particles (D) was measured by the same method as for the thermally conductive inorganic particles (A). The refractive index of the surface-treated inorganic particles (D) was the literature value of the refractive index of the thermally conductive inorganic particles (A).
[The bulk density]
The bulk density of the surface-treated inorganic particles (D) was measured using a Scott volume meter (ASTM-B-329-98 model manufactured by Tsutsui Rikagaku Kikai Co., Ltd.). The surface-treated inorganic particles (D) powder was put through a sieve (75φ×20 mm, opening 2000 μm) from the top until it overflowed from the stainless steel sample container, and when it overflowed, the excess amount was immediately scraped off using a slide glass. Its mass was weighed. The bulk density was calculated by the following formula.
Bulk density (g/mL) = (measured mass (g)) ÷ (sample container density (25 mL))

The surface-treated inorganic particles (D) of Examples 1 to 21 all have a water content of 0.2% by mass or less and a degree of hydrophobicity within the range of 35 to 95%, and the surface-treated inorganic particles (D) are 100 parts by mass. The amount of the silane compound was within the range of 0.05 to 3 parts by mass.
On the other hand, the inorganic particles of Comparative Example 1 using a titanate-based surface treatment agent had a water content of 0.15%, a hydrophobicity of 20%, and a pH of 7.2. The surface-treated inorganic particles of Comparative Examples 4 to 7 and 9 using various silane compounds had a degree of hydrophobicity of 0%. In the surface-treated inorganic particles of Comparative Examples 4 and 5, large, hard-to-crush aggregate particles of several millimeters were formed, and it was difficult to disaggregate them uniformly.

[Examples 13, 14, 19 to 20, Comparative Examples 7 and 8]
FIG. 2E shows the results of the heating weight loss rate test and hydrophobicity of the surface-treated inorganic particles (D) and the like. The heat weight loss rate test was performed by the following method. Hydrophobicity is as described above. In the heating weight loss rate test, the heating weight loss rate of the thermally conductive inorganic particles (A) is A1, and the heating weight loss of the surface-treated inorganic particles (D) obtained by surface-treating the thermally conductive inorganic particles (A). The rate was set to D1, and the difference between D1 and A1 was evaluated.
Heating weight loss rates A1 and D1 were calculated from weight loss amounts measured using a thermogravimetric meter. The weight loss of a thermogravimetric meter (differential thermal-thermogravimetric simultaneous measurement device (Thermo plus EVO2 TG-DTA8122, manufactured by Rigaku)) was measured by heating 5 mg of a sample to 40°C at a heating rate of 10°C/min in a nitrogen atmosphere. to 140° C., maintained at 140° C. for 5 minutes, and then further heated to 300° C. at a rate of temperature increase of 10° C./min. The evaluation results are shown in Table 2E.
The evaluation criteria were as follows.
++: (A1-D1) is 0.8% or more (good).
+: (A1-D1) is 0.5% or more and less than 0.8% (acceptable).
NG: (A1-D1) is less than 0.5% (defective).

Examples 13, 14, 21 and Comparative Examples 7, 8 are surface-treated inorganic particles obtained by using aluminum hydroxide B as the thermally conductive inorganic particles (A). Further, Examples 19 and 20 are comparisons before and after the surface treatment of aluminum hydroxides E and F, respectively. From these results, it can be seen that good heat weight loss rate test results can be obtained by surface treatment with the silane compound of general formula (1) so that the degree of hydrophobicity is 35% or more. The reason for this is speculative, but it is believed that the presence of the surface treatment layer inhibited the release of water contained in the chemical structure of the thermally conductive inorganic particles (A).

<Dispersant (B)>
- Dispersant 1B: ESLIM 221P (manufactured by NOF CORPORATION). Acid dispersant (100% active ingredient), weight average molecular weight 610, acid value 170 mgKOH/g, water content 0.8%.
Dispersant 1C: Synthetic product B1 (Synthesis Example 1-1, active ingredient 100%), a polymer having a polyester structure. A number average molecular weight of 2430, a weight average molecular weight of 3590, an acid value of 49 mgKOH/g, a water content of 0.01%, and a content of compounds having a molecular weight of 500 or less and having active hydrogen excluding water is 0%.
Dispersant 1E: Solsperse 21000 (manufactured by Lubrizol), a polymer having a polyester structure. Polymer of 12-hydroxystearic acid (100% active ingredient), weight average molecular weight 2500, acid value 74 mgKOH/g, water content 0.16%.
- Dispersant 1F: Spredox D-331 (manufactured by DOXA). Polyether compound having amine functional group (100% active ingredient), weight average molecular weight 23000, acid value 12 mgKOH/g, amine value 28 mgKOH/g, water content 0.2%.
Dispersant 2A: Synthetic product B1 (Synthesis Example 1-1, active ingredient 100%), same as Dispersant 1C.
Dispersant 2B: Synthetic product B2 (Synthesis Example 1-2, active ingredient 100%), a polymer having a polyether structure. A number average molecular weight of 1600, a weight average molecular weight of 2440, an acid value of 99 mgKOH/g, a water content of 0.01%, and a content of compounds having a molecular weight of 500 or less having active hydrogen excluding water of 0.5%.
Dispersant 2C: Synthetic product B3 (Synthesis Example 1-3, active ingredient 100%), a polymer having a polyester structure. A number average molecular weight of 1420, a weight average molecular weight of 1640, an acid value of 93 mgKOH/g, a water content of 0.01%, and a content of compounds having a molecular weight of 500 or less having active hydrogen excluding water of 0.8%.
• Dispersant 2D: ESLIM C-2093I (manufactured by NOF Corporation, 100% active ingredient), a urethane acrylate polymer having an ethylene glycol unit. Weight average molecular weight 1800, acid value 105 mgKOH/g, water content 0.1%.
Dispersant 2E: Ajisper PB821 (manufactured by Ajinomoto Fine-Techno Co., Inc.), a polymer having a polyester structure. Copolymer of main chain polyallylamine and side chain polycaprolactone. Weight average molecular weight 50000, acid value 17 mgKOH/g, amine value 10 mgKOH/g, water content 0.97%.
Dispersant 2H: Marialim SC-0505K (manufactured by NOF Corporation), a vinyl polymer having a polyether structure in the side chain. A copolymer having (anhydrous) maleic acid units and (poly)alkyleneoxy group-containing allyl ether units (100% active ingredient). Weight average molecular weight 10000, acid value 155 mgKOH/g, water content 0.02%.
Dispersant 2I: Solsperse 24000GR (manufactured by Lubrizol), a polymer having a polyester structure. Main chain polyethyleneimine, side chain 12-hydroxystearic acid copolymer (100% active ingredient), weight average molecular weight 5900, acid value 25 mgKOH/g, amine value 40 mgKOH/g, water content 1%.
Dispersant 2M: EFKA PX-4701 (manufactured by BASF), a vinyl polymer having a polyether structure in the side chain. Acrylic resin having pyridine as a basic functional group (100% active ingredient), weight average molecular weight 23000, acid value 0 mgKOH/g, amine value 40 mgKOH/g, water content 0.2%.
- Dispersant 2P: Joncryl682 (manufactured by BASF). Styrene-acrylic copolymer (active ingredient 100%), weight average molecular weight 1700, acid value 238 mgKOH/g, water content 0.38%.
- Dispersant 4F: ARUFON UH-2000 (manufactured by Toagosei Co., Ltd.). Acrylic polymer (active ingredient 100%), weight average molecular weight 11000, acid value 0 mgKOH/g, hydroxyl value 20 mgKOH/g, water content 0.02%.
Dispersants 2A to 2E, 2H, 2I and 2P are dispersants having carboxyl groups. Further, in the dispersants 2A to 2E, 2H, 2I, 2M, 2P and 4F, the amine value of the dispersants not described is 0.

<Synthesis of Dispersant (B)>
[Synthesis Example 1-1]: Synthetic Product B1
62.6 parts of 1-dodecanol, 287.4 parts of ε-caprolactone, and 0.1 part of monobutyltin (IV) oxide as a catalyst were charged into a reaction vessel equipped with a gas inlet tube, a thermometer, a condenser, and a stirrer, and nitrogen gas was added. and then heated and stirred at 120° C. for 4 hours. After confirming that 98% of the acid anhydride has reacted by solid content measurement, 36.6 parts of pyromellitic anhydride is added thereto and allowed to react at 100°C for 5 hours. After confirmation of esterification, the reaction was terminated. The resulting synthetic product B1 was a waxy solid at 25° C. and had a number average molecular weight of 2430, a weight average molecular weight of 3590 and an acid value of 49 mgKOH/g.

[Synthesis Example 1-2]: Synthetic Product B2
20.07 parts of 1-dodecanol, 79.93 parts of ε-caprolactone, and 0.1 part of monobutyltin (IV) oxide as a catalyst were charged into a reaction vessel equipped with a gas inlet tube, a thermometer, a condenser, and a stirrer, and nitrogen gas was added. and then heated and stirred at 120° C. for 4 hours. After confirming that 98% had reacted by solid content measurement, 20.70 parts of trimellitic anhydride was added thereto and allowed to react at 130°C for 4 hours. After confirming half-esterification, the reaction was terminated. The resulting synthetic product B2 was a waxy solid at 25° C. and had a number average molecular weight of 1600, a weight average molecular weight of 2440 and an acid value of 99 mgKOH/g.

[Synthesis Example 1-3]: Synthetic Product B3
In a reaction vessel equipped with a gas inlet tube, a thermometer, a condenser and a stirrer, Uniox M1000 (manufactured by NOF Corporation, polyoxyethylene monomethyl ether, number average molecular weight 1000) 100.0 parts, trimellitic anhydride 19.21 and reacted at 130° C. for 4 hours. After confirming that 97% or more of the acid anhydride was half-esterified by measuring the acid value, the reaction was terminated. The resulting synthetic product B3 was a gel-like soft solid at 25° C. and had a number average molecular weight of 1420, a weight average molecular weight of 1640 and an acid value of 93 mgKOH/g.

<Evaluation of Dispersant (B)>
The dispersants used in the examples were evaluated by measuring their water content, acid value, amine value and molecular weight distribution.
[Water content]
The water content of the dispersant (B) was determined by the same method as for the thermally conductive inorganic particles (A). The water content of the dispersant (B) was measured immediately before preparing the inorganic particle-containing composition.
[Acid value]
The acid value of the dispersing agent (B) is obtained by adding 80 mL of acetone and 10 mL of water to 0.5 to 1 g of the sample solution, stirring and uniformly dissolving, and using a 0.1 mol / L KOH aqueous solution as a titrant, automatic titration. An apparatus (“COM-555” manufactured by Hiranuma Sangyo Co., Ltd.) was used for titration to measure the acid value (mgKOH/g) of the sample solution. Then, the acid value per solid content of the sample was calculated from the acid value of the sample solution and the solid content concentration of the sample solution.
[Amine value]
The amine value of the dispersant (B) is a value obtained by converting the total amine value (mgKOH/g) measured according to ASTM D 2074 into solid content.
[Molecular weight distribution]
The molecular weight distribution of the dispersant (B) was determined by measuring the number average molecular weight (Mn) and weight average molecular weight (Mw) by gel permeation chromatography (GPC) equipped with an RI detector. HLC-8220GPC (manufactured by Tosoh Corporation) was used as an apparatus, two separation columns were connected in series, and "TSK-GEL SUPER HZM-N" was used as both packing materials, and the oven temperature was 40. °C, THF was used as an eluent, and the flow rate was 0.35 mL/min. The sample was dissolved in THF so as to have a concentration of 1 mass%, and 20 microliters of the solution was injected. All molecular weights are polystyrene equivalent values.

<Polyisocyanate compound (C1)>
• Reactive organic solvent C1-1: Duranate A201H (manufactured by Asahi Kasei Corporation). 100% active ingredient, 20.6 mass% isocyanate group, bifunctional type, number average molecular weight 670, viscosity 180 mPa·s.
- Reactive organic solvent C1-2: Duranate D101 (manufactured by Asahi Kasei Corporation). 100% active ingredient, 19.7% by mass of isocyanate groups, bifunctional type, number average molecular weight of 620, viscosity of 800 mPa·s.
- Reactive organic solvent C1-3: Duranate TUL-100 (manufactured by Asahi Kasei Corporation). 100% active ingredient, 23.3% by mass of isocyanate groups, isocyanurate type, number average molecular weight of 560, viscosity of 700 mPa·s.

<Polyol compound (C2)>
- Reactive organic solvent C2-1: Plaxel 303 (manufactured by Daicel). Polycaprolactone triol, active ingredient 100%, number average molecular weight 360, hydroxyl value 540 KOHmg/g, viscosity 3400 mPa·s.

<Additive>
・ Defoamer: Floren AC-326F (manufactured by Kyoeisha Chemical Co., Ltd., vinyl ether polymer)

<Evaluation of Inorganic Particle-Containing Composition>
Inorganic particle-containing compositions according to Examples and the like were manufactured by the manufacturing method described later. Then, the inorganic particle-containing composition was evaluated for viscosity (handleability), water content, and storage stability according to the following criteria.

[amount of water]
The water content of the inorganic particle-containing composition was measured using a Karl Fischer moisture meter (“CA-200” manufactured by Mitsubishi Chemical Analytech Co., Ltd., coulometric method). A 3 g sample was heated at 140° C. and the vaporized water content was measured.
[viscosity]
The viscosities of the inorganic particle-containing compositions produced in Preparation Examples (1) to (5) to be described later were measured by stirring and mixing the samples for 30 seconds with a Mixer Mixer (manufactured by Thinky Corporation, 2000 rpm), and then immediately using a Brookfield viscometer. ("HB" manufactured by Eko Seiki Co., Ltd., spindle SC4-14 when the viscosity value of the sample is 200 Pa s or less, spindle SC4-25 when the viscosity value exceeds 200 Pa s) was used to set the sample temperature to 25 ° C., Measurement was performed at a spindle rotation speed of 50 rpm and a measurement time of 1 minute. In Table 3A, "NG" was entered as the viscosity measurement value, indicating that the viscosity value exceeded 500 Pa s and there was almost no fluidity, and was entered as "-". The one indicates that the coarse particles contained in the inorganic particles could not be sufficiently clarified, and the spindle and the coarse particles came into contact during the measurement and were unsuitable as evaluation samples. The evaluation criteria were as follows.
+++: Viscosity value is 0 Pa·s or more and 100 Pa·s or less (particularly good).
++: More than 100 Pa·s and 200 Pa·s or less (good).
+: more than 200 Pa·s and 500 Pa·s or less (possible).
NG: more than 500 Pa·s (defective).
[Storage stability]
The storage stability of the inorganic particle-containing composition produced in Preparation Examples (1) to (5) described later was determined from the viscosity change rate after the inorganic particle-containing composition was stored at 35 ° C. for 3 hours. evaluated. The smaller the rate of change in viscosity, the better the results of the storage stability test. The viscosity change rate was calculated from the following formula using the viscosity value when the sample temperature was 25°C. In addition, those marked with "-" in the viscosity change rate indicate that the viscosity value after the storage stability test exceeded 500 Pa·s and could not be evaluated.
Viscosity change rate = (viscosity value after standing at 35 ° C. for 3 hours) / (viscosity value immediately after sample preparation)
In addition, the evaluation criteria were as follows.
<When only the polyisocyanate compound (C1) is included as the reactive organic solvent (C)>
++: Viscosity change rate is 0.5 or more and 2.0 or less (good).
+: Viscosity change rate is more than 2.0 and 5.0 or less (acceptable).
NG: Viscosity change rate exceeds 5.0 (unsuitable for long-term storage, poor).
<Case containing polyisocyanate compound (C1) and polyol compound (C2) as reactive organic solvent (C)>
++: Viscosity change rate is 1.0 or more and 5.0 or less (good).
+: Viscosity change rate is more than 5.0 and 12.0 or less (acceptable).
NG: Viscosity change rate exceeds 12 (pot life is short, poor).

<Preparation of composition containing inorganic particles (1)>
[Example 22]
According to the composition shown in Table 3A, 78 parts of the surface-treated inorganic particles (D) prepared in Production Example p1-4 (see Table 2A) were placed in a plastic container, 21.22 parts of Duranate A201H as a reactive organic solvent (C), 0.78 part of Spredox D-331 was charged as a dispersant (B). Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition. The moisture content of the resulting composition containing inorganic particles was 0.1%. The evaluation results are shown in Table 3A.

[Examples 23 to 30]
Inorganic particle-containing compositions of Examples 23 to 30 were prepared in the same manner as in Example 22, except that the materials and amounts used in Example 22 were changed as shown in Table 3A.

[Example 31]
According to the composition shown in Table 3B, 39 parts of the surface-treated inorganic particles (D) produced in Production Example p1-3 in a plastic container, 39 parts of aluminum oxide B, and 7.52 parts of Duranate A201H as a polyisocyanate compound (C1). , 7.51 parts of Duranate TUL-100, 6.40 parts of Plaxel 303 as a polyol compound (C2), 0.47 parts of a dispersant (B), and 0.1 part of Floren AC-326F as an antifoaming agent. is. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition.

[Examples 32 and 33]
Inorganic particle-containing compositions of Examples 32 and 33 were produced in the same manner as in Example 31, except that the materials of Example 31 and their amounts used were changed as shown in Table 3B.

[Comparative Examples 21 to 27]
Inorganic particle-containing compositions of Comparative Examples 21 to 27 were prepared in the same manner as in Example 22, except that the materials of Example 22 and their amounts used were changed as shown in Table 3A. Comparative Example 26 is a composition obtained by adding hexyltriethoxysilane to aluminum oxide C (Comparative Example 3 (manufacturing example Cp1-5)) that has not been subjected to surface treatment, immediately before the kneading treatment. is. Comparative example 27 is also the same.

The inorganic particle-containing compositions obtained in Examples 22 to 30 all had viscosities of 100 Pa s or less and good handling properties, and furthermore, the viscosity change rate was 5.0 or less, and the results of the storage stability test were also good. It was good. In addition, the inorganic particle-containing compositions containing the polyisocyanate compound (C1) and the polyol compound (C2) obtained in Examples 31 to 33 all have a viscosity of 100 Pa s or less and good handling properties, and are storage stable. Even after the property test, the fluidity was in a good state. By subjecting the thermally conductive inorganic particles (A) to a surface treatment with a specific silane compound and controlling the degree of hydrophobicity to be 35 to 95% and the water content to be 0.2% by mass or less, a reactive organic solvent (C ), the interaction and reactivity with the polyisocyanate compound (C1) could be effectively suppressed.

The composition of Comparative Example 25 almost lost fluidity after the storage stability test, and the test result was poor.

On the other hand, the compositions of Comparative Examples 21 and 24 were each obtained using inorganic particles treated with a surface treatment agent having an acidic functional group, and the composition of Comparative Example 23 had an amino It is obtained using inorganic particles treated with a surface treating agent having a group. Although these compositions appeared to have remarkably low viscosities immediately after preparation, many coarse particles of 1 mm or more that were extremely hard and difficult to disentangle remained.
When these surface-treated inorganic particles are used, polarity is imparted to the surface of the particles, making the particles easier to disperse and significantly reducing the viscosity. On the other hand, however, it is thought that part of the polar functional groups strongly bound the surface-treated inorganic particles to each other, resulting in the formation of extremely hard coarse particles.

In the composition of Comparative Example 22, not only were coarse particles that firmly adhered together not unraveled, but also the viscosity was very high and the storage stability was poor.
On the other hand, the compositions of Comparative Examples 26 and 27 have remarkably low viscosities immediately after preparation, because the silane compound functions as a low-viscosity solvent component. The rate of change in viscosity after the storage stability test was very high, and the product had a very strong silane compound odor, making it unsuitable for practical use.
A silane compound component that does not effectively act as a surface treatment agent for the thermally conductive inorganic particles (A) is considered to have a significant adverse effect on the storage stability of the inorganic particle-containing composition.

<Preparation of composition containing inorganic particles (2)>
[Example 41]
According to the composition shown in Table 4, 44 parts of the surface-treated inorganic particles (D) produced in Production Example p1-3 in a plastic container, 44 parts of aluminum oxide B, and 3.9 parts of Duranate A201H as a polyisocyanate compound (C1). , 3.9 parts of Duranate TUL-100, 3.22 parts of PLAXEL 303 as a polyol compound (C2), 0.88 parts of a dispersant (B), and 0.1 part of Floren AC-326F as an antifoaming agent. is. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition.

[Examples 42 to 47, Comparative Examples 41 and 42]
Compositions of Examples 42 to 47 and Comparative Examples 41 and 42 were prepared in the same manner as in Example 41, except that the materials of Example 41 and their amounts used were changed as shown in Table 4. The total amount of inorganic particles (E) in Examples and Comparative Example 42 was 88 parts, and the total amount of inorganic particles (E) in Comparative Example 41 was 85 parts.

<Preparation of thermally conductive cured product>
[Example 51]
The inorganic particle-containing composition prepared in Production Example p3-2 was filled in a plastic container (a circular container with a depth of 8 mm and a diameter of 4 cm) so as to be smooth, and then sufficiently degassed under reduced pressure at room temperature. Then, after standing at 30° C. for 6 hours, it was further left at 40° C. for 6 hours. After confirming that the inorganic particle-containing composition filled in the plastic container was sufficiently cured, the composition was taken out from the plastic container to obtain a thermally conductive cured product. The thermally conductive cured product thus obtained was evaluated by measuring its curability, foamability and thermal conductivity. Table 5 shows the evaluation results.

[Examples 52 to 57, Comparative Examples 51 and 52]
Cured products of Examples 52 to 57 and Comparative Examples 51 and 52 were produced in the same manner as in Example 51 except that the inorganic particle-containing composition was changed as shown in Table 5.

[Evaluation of curability and evaluation of foamability of thermally conductive cured product]
The curability and foamability of the thermally conductive cured product were evaluated by visual evaluation of the curable composition after standing at 30° C. for 6 hours and at 40° C. for 6 hours.
Regarding the curability evaluation, ++ (good) is sufficiently hardened, + (acceptable) is sufficiently hardened but bends when taken out of the container, and NG is not sufficiently cured. (impossible).
Regarding the evaluation of foamability, from the liquid surface when filling the plastic container so that it is smooth, the swelling is less than 0.5 mm +++ (very good), 0.5 mm or more and less than 1 mm is ++ (good ), those of 1 mm or more and less than 2 mm were rated as + (acceptable), and those of 2 mm or more were rated as NG (impossible).
[Evaluation of thermal conductivity]
Using each thermally conductive cured material prepared in Examples etc. as a measurement sample, a thermal conductivity measuring machine Hot Disc TPS500 (manufactured by Hot Disc AB, measuring terminal Kapton Sensors, Bulk (TYPE I, Isotropic), Heating power 1.5 W , measurement time of 10 seconds, measurement temperature of 25 degrees), and the measurement terminals were set so as to be sandwiched between the flat surfaces of the two measurement samples.
The obtained measurement results were analyzed for analysis data points 10 to 200 by Fine-tuned Analysis using Hot Disc Software Ver. 6.0, and the calculated value was defined as thermal conductivity.

The thermally conductive cured products of Examples 51 to 57 all exhibited good curability, foamability and thermal conductivity.
On the other hand, the thermally conductive cured product of Comparative Example 51 was very poor in curability, resulting in insufficient curing. In addition, the thermally conductive cured product of Comparative Example 52 was cured, but expanded significantly, and the thermal conductivity could not be evaluated. In either case, it is considered that the side reaction progressed between the liberated silane compound or moisture and the isocyanate group.

<Preparation of composition containing inorganic particles (3)>
[Example 61 (Production Example q1-2)]
According to the composition shown in Table 6, in a plastic container, 81 parts of the surface-treated inorganic particles (D) of Production Example p1-3, 18.19 parts of Duranate A201H as a reactive organic solvent (C), and 2A as a dispersant (B) (Synthetic product 1-1) was charged in an amount of 0.81 parts. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition. The moisture content of the resulting composition containing inorganic particles was 0.1%. Table 6 shows the evaluation results.

[Examples 62 to 73, Comparative Example 61]
Examples 62 to 73 and Comparative Example 61 were prepared in the same manner as in Example 61, except that the materials of Example 61 and the amounts used thereof were changed as shown in Table 6. In Example 65, as the surface-treated inorganic particles (D), the surface-treated inorganic particles (D) prepared in Production Example p1-2 and the surface-treated inorganic particles (D) prepared in Production Example p1-3 were mixed at 1:1. A mixture of 1 was used.

The inorganic particle-containing compositions of Examples 61 to 73 all had viscosities of 100 Pa·s or less and good handling properties, and further had viscosity change rates of 5.0 or less and good storage stability. From the comparison of Examples 61-64 and 66-71, in particular, having a carboxyl group as a dispersant (B), an acid value of 5 to 150 mgKOH / g, an amine value of 0 to 30 mgKOH / g, a weight average molecular weight of 1000 to 50000 It can be seen that the use of a polymeric dispersant makes it possible to disperse the thermally conductive inorganic particles (A) and the surface-treated inorganic particles (D) in the reactive organic solvent (C) at a high concentration. Further, from a comparison of Examples 61 to 64 with 66 and 71, it can be seen that the smaller the amine value of the dispersant (B), the smaller the viscosity change rate and the better the storage stability of the composition. It can be inferred that by setting the acid value and amine value of the polymeric dispersant within the above ranges, reactivity and interaction with isocyanate groups could be effectively suppressed.

On the other hand, the composition of Comparative Example 61 had a viscosity of more than 500 Pa·s and had almost no fluidity after the storage stability test, and was unsatisfactory.

<Preparation of composition containing inorganic particles (4)>
[Example 74]
According to the composition shown in Table 7, 40 parts of the surface-treated inorganic particles (D) produced in Production Example p1-3 in a plastic container, 40 parts of aluminum oxide B, and 8.94 parts of Duranate A201H as a polyisocyanate compound (C1). , 4.45 parts of Duranate TUL-100, 5.69 parts of PLAXEL 303 as a polyol compound (C2), 0.80 parts of a dispersant (B), and 0.12 parts of Floren AC-326F as an antifoaming agent. is. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition. Table 7 shows the evaluation results.

[Examples 75-78]
Compositions of Examples 75 to 78 were prepared in the same manner as in Example 74, except that the materials of Example 74 and the amount used thereof were changed as shown in Table 7.

All of the inorganic particle-containing compositions of Examples 74 to 78 had viscosities of 100 Pa·s or less and good handling properties, and had good fluidity even after the storage stability test. In particular, Examples 74 to 76 had a viscosity change rate of 5.0 or less, and the results of the storage stability test were also good.

<Preparation of composition containing inorganic particles (5)>
[Example 81]
According to the composition shown in Table 8, 8.6 parts of the surface-treated inorganic particles (D) prepared in Production Example p1-8 in a plastic container as inorganic particles (a1), 43 parts of aluminum oxide B as inorganic particles (a2), 34.4 parts of aluminum oxide A as the inorganic particles (a3), 4.56 parts of Duranate A201H as the polyisocyanate compound (C1), 4.56 parts of Duranate TUL-100, 3 PLAXEL 303 as the polyol compound (C2) .92 parts, 0.86 parts of dispersant (B), and 0.1 part of Floren AC-326F as an antifoaming agent were charged. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition.

[Examples 82-93]
Examples 82 to 93 were produced in the same manner as in Example 81, except that the materials and amounts used in Example 81 were changed as shown in Table 8. The total amount of inorganic particles (E) in each example except Example 91 was 86 parts, and the total amount of inorganic particles (E) in Example 91 was 90 parts.
The surface-treated inorganic particles used as the inorganic particles (a1) are all the surface-treated inorganic particles (D) produced in Production Example p1-8, and the surface-treated inorganic particles used as the inorganic particles (a2) are all produced in Production Examples. The surface-treated inorganic particles (D) produced in r-10, and the surface-treated inorganic particles (D) used as the inorganic particles (a3) are all the surface-treated inorganic particles (D) produced in Production Example p1-1.

<Production of thermally conductive cured product>
[Example 101]
The inorganic particle-containing composition prepared in Production Example r1-2 was completely filled in a plastic container (a circular container with a depth of 8 mm and a diameter of 4 cm), and then sufficiently degassed under reduced pressure at room temperature. Then, after standing at 30° C. for 6 hours, it was further left at 40° C. for 6 hours. After confirming that the inorganic particle-containing composition filled in the plastic container was sufficiently cured, the composition was taken out from the plastic container to obtain a thermally conductive cured product. The thermally conductive cured product thus obtained was evaluated by measuring curability, foamability, and thermal conductivity. Table 9 shows the evaluation results.

[Examples 102 to 113]
Cured products of Examples 102 to 113 were produced in the same manner as in Example 101 except that the inorganic particle-containing composition of Example 101 was changed as shown in Table 9.

All of the thermally conductive cured products of Examples 101 to 113 had good fillability into containers.

(Curability evaluation of thermally conductive cured product, foam evaluation)
Curability evaluation and foamability evaluation of the thermally conductive cured product were performed by visual evaluation of the curable composition after standing at 30° C. for 6 hours and 40° C. for 6 hours for Examples 101 to 113.
Regarding the curability evaluation, ++ (good) is sufficiently hardened, + (acceptable) is sufficiently hardened but bends when taken out of the container, and NG is not sufficiently cured. (impossible).
Regarding the evaluation of foamability, from the liquid surface when filling the plastic container so that it is smooth, the swelling is less than 0.5 mm +++ (very good), 0.5 mm or more and less than 1 mm is ++ (good ), those of 1 mm or more and less than 2 mm were rated as + (acceptable), and those of 2 mm or more were rated as NG (impossible).

(Evaluation of thermal conductivity)
Using the thermally conductive cured products of Examples 101 to 113 as measurement samples, a thermal conductivity measuring machine Hot Disc TPS500 (manufactured by Hot Disc AB, measuring terminal Kapton Sensors, Bulk (TYPE I, Isotropic), heating power 1.5 W, Measurement time was 10 seconds, measurement temperature was 25 degrees), and measurement was performed by setting the measurement terminals so as to be sandwiched between the flat surfaces of the two measurement samples.
The obtained measurement results were analyzed for analysis data points 10 to 200 by Fine-tuned Analysis using Hot Disc Software Ver. 6.0, and the calculated value was defined as thermal conductivity.
Regarding the evaluation of thermal conductivity, 3.0 W/m K or more is particularly good, 2.8 W/m K or more and less than 3.0 W/m K is good, and 2.5 W/m K or more. Those with less than 2.8 W/m·K were accepted.

The thermally conductive cured products of Examples 101 to 113 all exhibited good curability, foamability and thermal conductivity. From Examples 101 to 113, it can be seen that the combined use of the inorganic particles (a1) to (a3) in a predetermined ratio makes it possible to obtain a cured product with good thermal conductivity. Moreover, particularly when the value of (Y/X)×1000 is 1.0 to 5.0, particularly good curability, foamability and thermal conductivity can be obtained.
Examples 104 to 110 are cases in which the content ratio of the surface-treated inorganic particles (D) is 10 to 100% in 100% by mass of the inorganic particles (E). properties, foamability, and thermal conductivity can be obtained.

<Preparation of composition containing inorganic particles (6)>
[Example 121]
According to the composition shown in Table 10, 57.8 parts of the surface-treated inorganic particles (D) prepared in Production Example p1-16 were placed in a plastic container, and other inorganic particles (E) (thermally conductive inorganic particles (A)) were oxidized. 24.7 parts of aluminum C, 17.0 parts of Duranate A201H as polyisocyanate compound (C1), and 0.50 part of dispersant (B) were charged. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition. Table 10 shows the evaluation results.

[Examples 122 to 128, Comparative Examples 121 to 126]
Compositions of Examples 122 to 128 and Comparative Examples 121 to 126 were prepared in the same manner as in Example 121, except that the materials in Example 121 and their amounts used were changed as shown in Table 10.

[viscosity]
The viscosity of the inorganic particle-containing composition produced in Preparation Example (6) was measured in the same manner as in Preparation Example (1), etc., except for the following points. That is, the spindle rotation speed was changed to 20 rpm. Also, the viscosity in the table is 20 rpm viscosity. Moreover, the evaluation criteria were as follows. In Table 10, "NG" in the measured viscosity value indicates that the viscosity value exceeded 500 Pa·s and the fluidity was almost non-existent.
++: Viscosity value is 0 Pa·s or more and 200 Pa·s or less (good).
+: more than 200 Pa·s and 500 Pa·s or less (possible).
NG: more than 500 Pa·s (defective).
[Storage stability]
The storage stability of the inorganic particle-containing composition produced in Preparation Example (6) was evaluated from the viscosity change rate B after the inorganic particle-containing composition was stored at 5°C for 24 hours. The smaller the viscosity change rate B, the better the result of the storage stability test. The viscosity change rate B was calculated from the following formula using the viscosity value when the sample temperature was 25°C. In addition, those marked with "-" in the viscosity change rate B indicate that the viscosity value after the storage stability test exceeded 500 Pa·s and could not be evaluated.
Viscosity change rate B = (viscosity value after standing at 5 ° C. for 24 hours) / (viscosity value immediately after sample preparation)
In addition, the evaluation criteria were as follows.
++: Viscosity change rate is 0.5 or more and 2.0 or less (good).
+: Viscosity change rate is more than 2.0 and 5.0 or less (acceptable).
NG: Viscosity change rate exceeds 5.0 (unsuitable for long-term storage, poor).

The inorganic particle-containing compositions obtained in Examples 121 to 128 all had viscosities that were easy to handle, had a viscosity change rate of 5.0 or less, and had good storage stability test results.
On the other hand, the compositions obtained in Comparative Examples 121 to 126 used aluminum hydroxides A to F that were not surface-treated, respectively. Viscosity increased, and many lump-like lumps were formed, making it unusable.

<Preparation of composition containing inorganic particles (7)>
[Example 141]
According to the composition shown in Table 11, 12.75 parts of the surface-treated inorganic particles (D) produced in Production Example s1-1 were placed in a plastic container, and other inorganic particles (E) (thermally conductive inorganic particles (A)) were oxidized. 21.25 parts of aluminum A, 51 parts of aluminum oxide B, 7.84 parts of C1-1 as a polyisocyanate compound (C1), 2.60 parts of C1-3, and 4.03 parts of C2-1, 0.43 part of dispersant (B) and 0.1 part of Floren AC-326F as an antifoaming agent were charged. Next, at room temperature, the mixture was stirred and kneaded for 2 minutes with a Thinky Mixer (manufactured by THINKY Co., Ltd., 2000 rpm) to prepare an inorganic particle-containing composition.

[Examples 142 to 146, Comparative Examples 141 to 146]
The same procedure as in Example 141 was performed except that the materials and amounts used in Example 141 were changed as shown in Table 11 to obtain compositions of Examples and Comparative Examples shown in Table 11. The total amount of the inorganic particles (E) in each example and each comparative example was 85 parts.

The inorganic particle-containing compositions obtained in Examples 141 to 146 all had viscosities with good handleability. On the other hand, the compositions obtained in Comparative Examples 141 to 146 had very high viscosity and could not be handled and could not be used.

<Preparation of thermally conductive cured product>
[Example 151]
The inorganic particle-containing composition prepared in Production Example s4-1 was completely filled in a plastic container (a circular container with a depth of 8 mm and a diameter of 4 cm), and then sufficiently degassed under reduced pressure at room temperature. Then, after standing at 30° C. for 6 hours, it was further left at 40° C. for 6 hours. After confirming that the inorganic particle-containing composition filled in the plastic container was sufficiently cured, the composition was taken out from the plastic container to obtain a thermally conductive cured product. The thermally conductive cured product thus obtained was evaluated by measuring its curability, foamability and thermal conductivity. Table 12 shows the evaluation results.

[Examples 152 to 156]
Cured products of Examples 152 to 156 were produced in the same manner as in Example 151 except that the inorganic particle-containing composition of Example 151 was changed as shown in Table 12.

(Curability evaluation of thermally conductive cured product, foam evaluation)
Curability evaluation and foamability evaluation of the thermally conductive cured products of Examples 151 to 156 were performed in the same manner as in Example 51 and the like. Curability and foamability were evaluated according to the same criteria as in Example 51.

(Evaluation of thermal conductivity)
Using the thermally conductive cured products of Examples 151 to 156 as measurement samples, the thermal conductivity was measured in the same manner as in Example 51. Using a thermal conductivity measuring machine Hot Disc TPS500 (manufactured by Hot Disc AB, measurement terminal Kapton Sensors, Bulk (TYPE I, Isotropic), heating power 1.5 W, measurement time 10 seconds, measurement temperature 25 degrees), the measurement terminal was set so as to be sandwiched between the flat surfaces of the two measurement samples.
The obtained measurement results were analyzed for analysis data points 10 to 200 by Fine-tuned Analysis using Hot Disc Software Ver. 6.0, and the calculated value was defined as thermal conductivity.
Regarding the evaluation of thermal conductivity, 2.5 W/m K or more is particularly good, 2.0 W/m K or more and less than 2.5 W/m K is good, and 1.8 W/m K or more. Those with less than 2.0 W/m·K were accepted.

The thermally conductive cured products of Examples 151 to 156 all exhibited good curability, foamability and thermal conductivity. It can be seen that particularly good thermal conductivity can be obtained when the unsubstituted alkyl group has 4 to 8 carbon atoms. Moreover, as shown in Example 155, particularly when inorganic particles (D) having a primary particle diameter of 1 to 10 μm and a BET specific surface area of 0.05 to 5 m ² /g are used, particularly excellent thermal conductivity is obtained. was able to obtain

Claims (24)

Thermally conductive inorganic particles (A) having an average primary particle diameter of 0.05 to 100 μm and a water content of 0.5% by mass or less , and a coating layer formed on the surfaces of the thermally conductive inorganic particles (A). Surface-treated inorganic particles (D),
The thermally conductive inorganic particles (A) are at least one selected from the group consisting of aluminum oxide, aluminum hydroxide, and boehmite ,
The coating layer is
General formula (1): Si(R ¹ )(R ² )(R ³ )(R ⁴ )
Having 50% by mass or more of a component derived from a silane compound represented by
However, two of R ¹ to R ⁴ in general formula (1) independently represent an alkoxy group or an aryloxy group, and the other two independently represent an unsubstituted alkyl group or a substituted and at ^{least one} selected from the group consisting of an alkyl group having a one represents at least one selected from the group consisting of an unsubstituted alkyl group, an alkyl group having a substituent, and a phenyl group, the substituent being a (meth)acrylic group or an isocyanate group;
When the thermally conductive inorganic particles (A) are aluminum oxide, the silane compound satisfies any of the following (I) to (III),
When the thermally conductive inorganic particles (A) are aluminum hydroxide or boehmite, the silane compound satisfies (IV) below,
The silane compound is 0.05 to 3% by mass with respect to 100% by mass of the surface-treated inorganic particles (D),
Surface-treated inorganic particles (D) for polyisocyanate-based compositions, having a water content of 0.2% by mass or less and a degree of hydrophobicity of 35% or more.
(I): At least one of R ¹ to R ⁴ is an unsubstituted alkyl group having 3 to 10 carbon atoms.
(II): At least two of R ¹ to R ⁴ are unsubstituted alkyl groups having 1 to 10 carbon atoms.
(III): At least two of R ¹ to R ⁴ are unsubstituted phenyl groups.
(IV): At least one of R ¹ to R ⁴ is an unsubstituted alkyl group having 6 to 10 carbon atoms. In the general formula (1), the substituent is a (meth)acryl group, the alkoxy group has 1 to 10 carbon atoms, the aryloxy group has 6 to 10 carbon atoms, and the unsubstituted alkyl group has 1 to 10, and the surface-treated inorganic particles (D) according to claim 1, having a degree of hydrophobicity of 40 to 95%. 2. The surface-treated inorganic particles (D) according to claim 1, wherein the thermally conductive inorganic particles (A) are non-spherical particles. 2. The method according to claim 1, wherein Dx/Ax=0.3 to 0.8, where Ax is the specific surface area of the thermally conductive inorganic particles (A) and Dx is the specific surface area of the surface-treated inorganic particles (D). Surface-treated inorganic particles (D). The surface treatment according to claim 1, wherein Dy/Ay is 0.05 to 1, where Ay is the water content of the thermally conductive inorganic particles (A) and Dy is the water content of the surface-treated inorganic particles (D). Inorganic particles (D). 2. The surface-treated inorganic particles (D) according to claim 1, having a powder particle size D50 of 1 to 100 μm and a bulk density of 0.3 to 2 g/cm ³ . containing inorganic particles (E) and a reactive organic solvent (C),
The inorganic particles (E) are
The surface-treated inorganic particles (D) according to any one of claims 1 to 6,
Optionally surface-treated thermally conductive inorganic particles (A) that do not correspond to surface-treated inorganic particles (D), and surface-treated inorganic particles (D) and thermally conductive inorganic particles that do not correspond to (A) Any one or more of the thermally conductive fillers (F) that may be
At least including surface-treated inorganic particles (D) as inorganic particles (E),
The thermally conductive filler (F) is an inorganic filler with a thermal conductivity of 5 W/(m K) or more,
The reactive organic solvent (C) is an inorganic particle-containing composition containing a polyisocyanate compound (C1). 8. The composition containing inorganic particles according to claim 7, further comprising a dispersant (B). 8. The composition containing inorganic particles according to claim 7, wherein the reactive organic solvent (C) further contains a polyol compound (C2). 5 to 40 parts by mass of the reactive organic solvent (C) and 0.01 to 4 parts by mass of the dispersant (B) per 100 parts by mass of the inorganic particles (E),
9. The inorganic particle-containing composition according to claim 8, wherein the dispersant (B) has a water content of 1% by mass or less. 8. The inorganic particle-containing composition according to claim 7, containing 70 to 95% by mass of the inorganic particles (E). 8. The inorganic particle-containing composition according to claim 7, comprising 10 to 100% by mass of the surface-treated inorganic particles (D) in 100% by mass of the inorganic particles (E). The amount of the surface-treated inorganic particles (D) contained in 100% by mass of the inorganic particles (E) is 10 to 100% by mass,
When the inorganic particles (E) are 100% by mass, the inorganic particles (a1) having an average primary particle diameter of 0.05 μm or more and 10 μm or less are 10 to 30% by mass, and the inorganic particles (a2) having an average primary particle diameter of more than 10 μm and 30 μm or less. 30 to 70% by mass, 15 to 40% by mass of inorganic particles (a3) having an average primary particle diameter of more than 30 μm and 100 μm or less, and the total of (a1), (a2) and (a3) is 80 to 100% by mass. ,
The reactive organic solvent (C) contains a polyisocyanate compound (C1) and a polyol compound (C2) as main components,
The inorganic material according to claim 8, wherein the amount of the reactive organic solvent (C) is 5 to 40 parts by mass and the amount of the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E). Particle-containing composition. 8. The inorganic particle-containing composition according to claim 7, wherein the polyisocyanate compound (C1) has a viscosity of 10 to 10,000 mPa·s at 25°C. The total surface area of the inorganic particles (a1) to (a3) per 100 g of the inorganic particles (E) is represented by Xm ² , which constitutes the coating layer of the surface-treated inorganic particles (D) and is represented by the general formula (1). 14. The inorganic particle-containing composition according to claim 13, wherein (Y/X)×1000 is 1.0 to 5.0 where Yg is the total amount of the silane compounds. comprising a dispersant (B), wherein the dispersant (B) is
an anionic surfactant having a carboxyl group, or
8. The inorganic particle-containing composition according to claim 7, comprising a polymeric dispersant having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 500 to 100,000. comprising a dispersant (B), wherein the dispersant (B) is
8. The inorganic particle-containing composition according to claim 7, comprising a polymeric dispersant having an acid value of 5 to 200 mgKOH/g and a weight average molecular weight of 1,000 to 50,000 and having a polyether structure or a polyester structure. comprising a dispersant (B), wherein the dispersant (B) is
A polymeric dispersant having a carboxyl group, an acid value of 5 to 150 mgKOH/g, an amine value of 0 to 30 mgKOH/g, and a weight average molecular weight of 1,000 to 50,000,
The inorganic particle-containing according to claim 7, wherein the reactive organic solvent (C) is 5 to 40 parts by mass and the dispersant (B) is 0.01 to 4 parts by mass with respect to 100 parts by mass of the inorganic particles (E). Composition. It contains a dispersant (B), and the dispersant (B) is a polymer type dispersant having a polyether structure or a polyester structure, a polymer having a polyether structure or a polyester structure in the main chain, and a side chain 8. The inorganic particle-containing composition according to claim 7, which is at least one selected from the group consisting of vinyl polymers having a polyether structure. 8. The inorganic particle-containing composition according to claim 7, wherein the viscosity change rate after 3 hours at 35° C. is 0.8 to 3.0. A thermally conductive cured product obtained by curing the inorganic particle-containing composition according to claim 7 and having a thermal conductivity of 1 to 8 W/(m·K). 22. The thermally conductive cured product according to claim 21, wherein the film thickness is 0.01 to 10 mm. A structure comprising a member (M1), a member (M2), and the thermally conductive cured product according to claim 21 formed between the member (M1) and the member (M2). A laminate comprising a sheet-like substrate (S1), the thermally conductive cured product according to claim 21, and a sheet-like substrate (S2) in this order.